Sample records for digital radiographic imaging

Full Text Available The aim of the present study was to evaluate the image quality of four direct digitalradiographic systems. Radiographs were made of the maxillary central incisor and mandibular left molar regions of a dry skull, and an aluminum step-wedge. The X-ray generator operated at 10 mA, 60 and 70 kVp, and images were acquired with 3, 5, 8, 12, 24 and 48 exposure pulses. Six well-trained observers classified the images by means of scores from 1 to 3. Collected data were submitted to nonparametric statistical analysis using Fisher's exact test. Statistical analysis showed significant differences (p<0.01 in image quality with the four systems. Based on the results, it was possible to conclude that: 1 all of the digital systems presented good performance in producing acceptable images for diagnosis, if the exposures of the step-wedge and the maxillary central incisor region were made at 5 pulses, as well as at 8 pulses for the mandibular left molar region, selecting 60 or 70kVp; 2 higher percentages of acceptable images were obtained with the administration of lower radiation doses in CCD-sensors (charge-coupled device; 3 the Storage Phosphor systems produced acceptable images at a large range of exposure settings, that included low, intermediate and high radiation doses.

Several studies have addressed the implications of filmless radiologic imaging on telemedicine, diagnostic ability, and electronic teaching files. However, many publishers still require authors to submit hard-copy images for publication of articles and textbooks. This study compares the quality digitalimages directly exported from picture archive and communications systems (PACS) to imagesdigitized from radiographic film. The authors evaluated the quality of publication-grade glossy photographs produced from digitalradiographicimages using 3 different methods: (1) film imagesdigitized using a desktop scanner and then printed, (2) digitalimages obtained directly from PACS then printed, and (3) digitalimages obtained from PACS and processed to improve sharpness prior to printing. Twenty images were printed using each of the 3 different methods and rated for quality by 7 radiologists. The results were analyzed for statistically significant differences among the image sets. Subjective evaluations of the filmless images found them to be of equal or better quality than the digitizedimages. Direct electronic transfer of PACS images reduces the number of steps involved in creating publication-quality images as well as providing the means to produce high-quality radiographicimages in a digital environment.

The present study was aimed to reveal the texture patterns of the radiographs of the mandibular trabeculae by digitalimage processing. The 32 cases of normal subjects and the 13 cases of patients with mandibular diseases of ameloblastoma, primordial cysts, squamous cell carcinoma and odontoma were analyzed by their intra-oral radiographs in the right premolar regions. The radiograms were digitized by the use of a drum scanner densitometry method. The input radiographicimages were processed by a histogram equalization method. The result are as follows : First, the histogram equalization method enhances the image contrast of the textures. Second, the output images of the textures for normal mandible-trabeculae radiograms are of network pattern in nature. Third, the output images for the patients are characterized by the non-network pattern and replaced by the patterns of the fabric texture, intertwined plants (karakusa-pattern), scattered small masses and amorphous texture. Thus, these results indicates that the present digitalimage system is expected to be useful for revealing the texture patterns of the radiographs and in the future for the texture analysis of the clinical radiographs to obtain quantitative diagnostic findings.

his study was performed to investigate the effect of image enhancement of periapical radiographs according to the diagnostic task. Eighty digital intraoral radiographs were obtained from patients and classified into four groups according to the diagnostic tasks of dental caries, periodontal diseases, periapical lesions, and endodontic files. All images were enhanced differently by using five processing techniques. Three radiologists blindly compared the subjective image quality of the original images and the processed images using a 5-point scale. There were significant differences between the image quality of the processed images and that of the original images (P<0.01) in all the diagnostic task groups. Processing techniques showed significantly different efficacy according to the diagnostic task (P<0.01). Image enhancement affects the image quality differently depending on the diagnostic task. And the use of optimal parameters is important for each diagnostic task.

Full Text Available OBJECTIVES: This study applied a simple method to evaluate the performance of three digital devices (two scanners and one digital camera using the reproducibility of pixel values attributed to the same radiographicimage. METHODS: Using the same capture parameters, a radiographicimage was repeatedly digitized in order to determine the variability of pixel values given to the image throughout the digitization process. One coefficient value was obtained and was called pixel value reproducibility. RESULTS: A significant difference in pixel values was observed among the three devices for the digitizedimages (ANOVA, p<0.00001. There was significant pixel value variability at the same digitization conditions for one scanner and the digital camera. CONCLUSIONS: Digital devices may assign pixel values differently in consecutive digitization depending on the optical density of the radiographicimage and the equipment. The pixel value reproducibility was not satisfactory as tested for two devices. It is maybe advisable knowing the digitization variations regarding pixel values whenever using digital radiography images in longitudinal clinical examinations.

The objective of this study was to compare the quality of radiographicimagesdigitized from commercial-grade and consumer-grade digital cameras and scanners as viewed on computer monitor. Radiographicimages were digitized from hardcopy film using a commercial-grade laser scanner, a consumer-grade desktop flatbed scanner, a commercial-grade digital camera, and a consumer-grade digital camera. The quality of images without and with grayscale histogram adjustment was evaluated subjectively by ...

Before a radiographicimage is sent to a picture archiving and communications system (PACS), its projection information needs to be correctly identified at capture modalities to facilitate image archive and retrieval. Currently, annotating radiographicimages is manually performed by technologists. It is labor intensive and cost ineffective. Moreover, man-made annotation errors occur frequently during image acquisition. To address this issue, an automatic image recognition method is developed. It first extracts a set of visual features from the most indicative region in a radiograph for image recognition, and then uses a family of classifiers, each of which is trained for a specific projection to determine the most appropriate projection for the image. The method has been tested on a large number of clinical images and has shown excellent robustness and efficiency.

Perona Malik Anisotropic Diffusion (PMAD) is a very useful and efficient denoising technique if the parameters are properly selected. Overestimating the parameters may cause oversmoothed and underestimating it may leave unfiltered noise. This makes the selection of parameters a crucial process. In this paper the PMAD model is solved using a finite difference scheme The discretized model is evaluated using different diffusion coefficient of exponential and quadratic on defective radiographicimages in terms of quality and efficiency. In the application of the PMAD model on image data, a set of defective radiographicimages of welding is used as input data. Peak Signal to Noise Ratio (PSNR), Structural Similarity Measure (SSIM) and temporal time are used to evaluate the performance of the model. The implementation of the experiment has been carried out using MATLAB R2009a. In terms of quality, results show that the Quadratic Diffusion Coefficient Function (QDCF) provides better results compared with the Exponential Diffusion Coefficient Function (EDCF). In conclusion, the denoising effect using PMAD model based on finite difference scheme shows able to improve image quality by removing noise in the defective radiographicimage.

Full Text Available The aims of this study were to evaluate the quality of indirect digitizedradiographicimages taken during endodontic procedures and to compare the measurements recorded with this technique to those obtained from conventional radiographs. Two-hundred conventional periapical radiographs taken at the undergraduate Endodontics Clinic of the Dental School of Bauru were digitized. The conventional and indirect digitizedimages were compared by three examiners as to the quality and accuracy of the measurements recorded during endodontic treatment, in canal length determination, gutta-percha adaptation, lateral condensation and final obturation. The conventional radiographs were observed on a film viewer, surrounded by a dark card, and measured with magnifying glass and a millimeter ruler; the indirect digitizedimages were evaluated on the Digora® for Windows software, with free utilization of the bright/contrast tool. Unlike the conventional radiographicimages, all indirect digitizedimages were considered as having a high quality. The distance between the filling material and the root apex was 0.117 mm larger, on average, for the Digora® system (p<0.01. The measurements achieved by the investigated radiographic methods were clinically similar and they are thus equivalent. Changes in brightness and contrast of the images using Digora®software improved the diagnosis.

The aims of this study were to evaluate the quality of indirect digitizedradiographicimages taken during endodontic procedures and to compare the measurements recorded with this technique to those obtained from conventional radiographs. Two-hundred conventional periapical radiographs taken at the undergraduate Endodontics Clinic of the Dental School of Bauru were digitized. The conventional and indirect digitizedimages were compared by three examiners as to the quality and accuracy of the measurements recorded during endodontic treatment, in canal length determination, gutta-percha adaptation, lateral condensation and final obturation. The conventional radiographs were observed on a film viewer, surrounded by a dark card, and measured with magnifying glass and a millimeter ruler; the indirect digitizedimages were evaluated on the Digora® for Windows software, with free utilization of the bright/contrast tool. Unlike the conventional radiographicimages, all indirect digitizedimages were considered as having a high quality. The distance between the filling material and the root apex was 0.117 mm larger, on average, for the Digora® system (p<0.01). The measurements achieved by the investigated radiographic methods were clinically similar and they are thus equivalent. Changes in brightness and contrast of the images using Digora® software improved the diagnosis. PMID:19089211

Full Text Available This study compared Kodak Ektaspeed film and Dexis digitalimaging systems for their diagnostic accuracy in detection of proximal canes in 210 proximal surfaces from 105 extracted human teeth (20 premolars and 85 molars, 129 of which were carious. Ground teeth were evaluated histologically. The images were assessed by an observer. ANOVA revealed that groups differ in scoring patterns with f-value of 26.72 and p < 0.01. The mean caries score by histologic assessment was significantly (p < 0.01 more when compared with the scores obtained by conventional and Dexis digitalradiographic methods. The mean score for conventional radiographic method was slightly more than Dexis digitalradiographic method, but the difference was statistically insignificant (p < 0.05. Both the radiographic methods were less accurate in detecting proximal canes confined to enamel, but as the lesion depth was increased to dentin, the rate of caries detection increased dramatically. It was concluded that both conventional and Dexis digitalradiographic methods under estimated canes depth when compared with histologic method. Lastly, conventional film radiographs and Dexis digitalradiographs did not perform significantly different from each other in the detection of canes.

The objective of this study was to compare the quality of radiographicimagesdigitized from commercial-grade and consumer-grade digital cameras and scanners as viewed on computer monitor. Radiographicimages were digitized from hardcopy film using a commercial-grade laser scanner, a consumer-grade desktop flatbed scanner, a commercial-grade digital camera, and a consumer-grade digital camera. The quality of images without and with grayscale histogram adjustment was evaluated subjectively by 10 board-certified radiologists. Optical density response was evaluated objectively using a grayscale test pattern. There was no significant difference in subjective quality among imagesdigitized with the commercial scanner, consumer scanner, and commercial camera. The quality of imagesdigitized with the consumer camera was lower than the other 3. Objective tests showed the commercial scanner to have the most linear optical density response. For the purpose of viewing images on a computer monitor, a consumer-grade desktop scanner can produce images of similar quality to those produced by more expensive laser commercial-grade scanners and digital cameras and provides cost-efficient means to digitizeradiographic plain films. A consumer-grade camera may not be optimal for use in this setting.

Aim: To determine whether radiologists can recognize images retouched to include sham lesions. Materials and methods: Ten representative key images were selected of aortic dissection, hepatocellular carcinoma, renal cell carcinoma, colon cancer, liver metastasis, hepatic cyst, gallbladder stones, splenic artery aneurysm, adrenal adenoma, and stomach cancer from abdominal computed tomography (CT) imaging performed in 2008. Five of the key images were replaced with retouched images using image-editing software. The time to complete retouching was recorded for each image. Radiologists were requested to make a diagnosis for the 10 images, and were then asked to identify possible retouched images. The time taken to reach a decision in each case was recorded. Thirty radiologists (13 residents and 17 attending radiologists) participated as reviewers. Results: The time to complete retouching was 15.2 {+-} 3.15 min. None of the reviewers recognized that some images were retouched during diagnosis. The rate of correct diagnosis was 90% (range 71.7-100%). After reviewers were informed of possible image retouching, the detection rate of retouched images was 50% (40-58.3%). This rate was statistically the same as random choice (p = 0.876). There was no significant difference between residents and attending radiologists in the detection rate of retouched images (p = 0.786). The time to diagnosis and the time to detection of the retouched images were 15 (14-17) and 6 (5-7) min, respectively. Conclusion: Digitalimages can be easily retouched, and radiologists have difficulty in identifying retouched images. Radiologists should be aware of the potential fraudulent use of retouched images.

Screen film radiography often fails to optimally display all regions of anatomy on muskuloskeletal exams due to the wide latitude of tissue densities present. Various techniques of image enhancement have been applied to such exams using computerized radiography but with limited success in improving visualization of structures whose final optical density lies at the extremes of the interpretable range of the film. An existing algorithm for compressing optical density extremes known as dynamic range compression has been used to increase the radiodensity of the retrocardiac region of the chest or to decrease the radiodensity of the edge of the breast in digital mammography. In the skeletal system, there are regions where a single image may contain both areas of decreased exposure that result in light images and areas of higher exposure that result in dark regions of the image. Faced with this problem, the senior author asked Fuji to formulate a modification of the DRC process that incorporates a combination of the curves used for chest and breast images. The newly designed algorithm can thus simultaneously lower the optical density of dark regions of the image and increase the optical density of the less exposed regions. The results of this modification of the DRC algorithm are presented in this paper.

Aim: To compare the use of film-based periapical radiographs and digital panoramic images displayed on monitor and glossy paper in the assessment of the periapical status of the teeth. Methodology: A total of 86 subjects were examined. All participants underwent a full-mouth radiographic survey (14 periapical radiographs) and a digital panoramic radiography. The periapical status of all appraised teeth was assessed. Results: Periapical radiographs allowed the assessment of the periapical ...

The aim of this work is to evaluate, through MCNPX simulations, several ways to minimize the scatter contribution in radiographicdigitalimages of offshore pipelines. The influence of liquid inside the pipes and water surrounded the pipelines in the scatter contribution will be analyzed. The use of lead screen behind the detector to reduce the backscattered radiation and filter between the radiation source and the pipes will be discussed. (author)

overall cost, particularly at high imaging volumes,1 reduced ... diagnostic potential, a clinical prototype was installed and evaluated .... is not only time consuming and labour ... and revenue analysis. .... a laboratory test designed to measure how much drug activity boosts the activity of SIRT1 may be providing false positives.

A total PACS will be inevitable for radiology practice within several years. To achieve a total PACS for radiology, a satisfactory digitalradiographic unit is required, because approximately 65% of digital data for PACS comes from digitalradiographs. There are several possibilities for producing digitalradiographs, and 3 - 4 companies have been marketing digitalradiographic devices. Some data regarding the digitalradiographic units on the market are compared. It will aid in assessing the current status and availability of this aspect of development, as well as providing a summary of further development of digitalradiographic technology.

In the last decades a new type of detector which is based on photostimulable luminescence was developed. There are currently many kinds of image plates (IPs) available on the market, originating from different manufacturers. Each kind of plate distinguishes itself from the others by its peculiar physical structure and composition, two factors which have a direct influence upon the quality of the digitalradiographicimages obtained through them. For this study, several kinds of IPs were tested in order to determine in which way such influence takes place. For this purpose, each kind of IP has been characterized and correlated to its response in the final image. The aim of this work was to evaluate procedures for employing Computed Radiography (CR) to welding inspections in laboratory conditions using the Simple Wall Simple Image Technique (SWSI). Tests were performed in steel welded joins of thickness 5.33, 12.70 and 25.40 mm, using CR scanner and IPs available on the market. It was used an X-Ray equipment as radiation source. The image quality parameters Basic Spatial Resolution (BSR), Normalized Signal-to-Noise Ratio (SNR{sub N}), contrast and detectability were evaluated. In order to determine in which way the IPs' properties are correlated to its response in the final image, the thickness of the sensitive layer was determined and the grain size and the elemental composition of this layer were evaluated. Based on the results drawn from this study, it is possible to conclude that the physical characteristics of image plates are essential for determining the quality of the digital radiography images acquired with them. Regarding the chemical composition of the plates, it was possible to determine that, apart from the chemical elements that were expected to be found (Ba, I and Br), only two plates, with high resolution, do not have fluorine in their composition; the presence of Strontium was also detected in the chemical composition of the plates supplied by a

Aim: To optimise the digital (radiographic) imaging of children presenting with suspected non-accidental injury (NAI). Objectives: (i) To evaluate existing radiographic quality criteria, and to develop a more suitable system if these are found to be inapplicable to skeletal surveys obtained in suspected NAI. (ii) To document differences in image quality between conventional film-screen and the recently installed Fuji5000R computed radiography (CR) system at Great Ormond Street Hospital for Children, (iii) To document the extent of variability in the standard of skeletal surveys obtained in the UK for suspected NAI. (iv) To determine those radiographic parameters which yield the highest diagnostic accuracy, while still maintaining acceptable radiation dose to the child, (v) To determine how varying degrees of edge-enhancement affect diagnostic accuracy. (vi) To establish the accuracy of soft compared to hard copy interpretation of images in suspected NAI. Materials and Methods: (i) and (ii) Retrospective analysis of 286 paediatric lateral spine radiographs by two observers based on the Commission of European Communities (CEC) quality criteria, (iii) Review of the skeletal surveys of 50 consecutive infants referred from hospitals throughout the United Kingdom (UK) with suspected NAI. (iv) Phantom studies. Leeds TO. 10 and TO. 16 test objects were used to compare the relationship between film density, exposure parameters and visualisation of object details, (iv) Clinical study. Anteroposterior and lateral post mortem skull radiographs of six consecutive infants were obtained at various exposures. Six observers independently scored the images based on visualisation of five criteria, (v) and (vi) A study of diagnostic accuracy in which six observers independently interpreted 50 radiographs from printed copies (with varying degrees of edge-enhancement) and from a monitor. Results: The CEC criteria are useful for optimisation of imaging parameters and allow the detection

This is the first part of a two-part study in benchmarking the performance of fixed digitalradiographic general X-ray systems. This paper concentrates on reporting findings related to quantitative analysis techniques used to establish comparative image quality metrics. A systematic technical comparison of the evaluated systems is presented in part two of this study. A novel quantitative image quality analysis method is presented with technical considerations addressed for peer review. The novel method was applied to seven general radiographic systems with four different makes of radiographicimage receptor (12 image receptors in total). For the System Modulation Transfer Function (sMTF), the use of grid was found to reduce veiling glare and decrease roll-off. The major contributor in sMTF degradation was found to be focal spot blurring. For the System Normalised Noise Power Spectrum (sNNPS), it was found that all systems examined had similar sNNPS responses. A mathematical model is presented to explain how the use of stationary grid may cause a difference between horizontal and vertical sNNPS responses.

This study was performed to compare the inverted digitalimages and film-based images of dry pig mandibles to measure the periodontal bone defect depth. Forty 2-wall bone defects were made in the proximal region of the premolar in the dry pig mandibles. The digital and conventional radiographs were taken using a Schick sensor and Kodak F-speed intraoral film. Image manipulation (inversion) was performed using Adobe Photoshop 7.0 software. Four trained examiners made all of the radiographic measurements in millimeters a total of three times from the cementoenamel junction to the most apical extension of the bone loss with both types of images: inverted digital and film. The measurements were also made in dry mandibles using a periodontal probe and digital caliper. The Student's t-test was used to compare the depth measurements obtained from the two types of images and direct visual measurement in the dry mandibles. A significance level of 0.05 for a 95% confidence interval was used for each comparison. There was a significant difference between depth measurements in the inverted digitalimages and direct visual measurements (p>|t|=0.0039), with means of 6.29 mm (IC{sub 95%}:6.04-6.54) and 6.79 mm (IC{sub 95%}:6.45-7.11), respectively. There was a non-significant difference between the film-based radiographs and direct visual measurements (p>|t|=0.4950), with means of 6.64 mm(IC{sub 95%}:6.40-6.89) and 6.79 mm(IC{sub 95%}:6.45-7.11), respectively. The periodontal bone defect measurements in the inverted digitalimages were inferior to film-based radiographs, underestimating the amount of bone loss.

The aim of the present study was to evaluate the use of common external image processing to compensate for differences in appearance between digital X-ray images from different vendors. Twenty posteroanterior chest radiographs were collected from each of three different modalities from different vendors (GE, Siemens and Canon) with vendor-specific image processing applied. The images were also extracted with neutral process parameters and processed with external image-processing software. Six experienced radiologists rated the quality and the similarity of the images with the original Siemens images. The externally processed GE images were rated of higher quality than the original GE images and more similar to the original Siemens images (p images. The externally processed Siemens images were rated of similar quality as the original images. The present study indicates the possibility of using common external image processing to harmonise the appearance of images from different vendors, although the exposure parameters may need to be adjusted for individual vendors.

The aims of the present study are to determine the optimum compression rate in terms of file size reduction and diagnostic quality of the images after compression and evaluate the transmission speed of original or each compressed images. The material consisted of 24 extracted human premolars and molars. The occlusal surfaces and proximal surfaces of the teeth had a clinical disease spectrum that ranged from sound to varying degrees of fissure discoloration and cavitation. The images from Digora system were exported in TIFF and the images from conventional intraoral film were scanned and digitalized in TIFF by Nikon SF-200 scanner(Nikon, Japan). And six compression factors were chosen and applied on the basis of the results from a pilot study. The total number of images to be assessed were 336. Three radiologists assessed the occlusal and proximal surfaces of the teeth with 5-rank scale. Finally diagnosed as either sound or carious lesion by one expert oral pathologist. And sensitivity and specificity and kappa value for diagnostic agreement was calculated. Also the area (Az) values under the ROC curve were calculated and paired t-test and oneway ANOVA test was performed. Thereafter, transmission time of the image files of the each compression level were compared with that of the original image files. No significant difference was found between original and the corresponding images up to 7% (1:14) compression ratio for both the occlusal and proximal caries (p<0.05). JPEG3 (1:14) image files are transmitted fast more than 10 times, maintained diagnostic information in image, compared with original image files. 1:14 compressed image file may be used instead of the original image and reduce storage needs and transmission time.

Communication between radiologists and clinicians could be improved if a secondary image (copy of the original image) accompanied the radiologic report. In addition, the number of lost original radiographs could be decreased, since clinicians would have less need to borrow films. The secondary image should be simple and inexpensive to produce, while providing sufficient image quality for verification of the diagnosis. We are investigating the potential usefulness of a video printer for producing copies of radiographs, i.e. images printed on thermal paper. The video printer we examined (Seikosha model VP-3500) can provide 64 shades of gray. It is capable of recording images up to 1,280 pixels by 1,240 lines and can accept any raster-type video signal. The video printer was characterized in terms of its linearity, contrast, latitude, resolution, and noise properties. The quality of video-printer images was also evaluated in an observer study using portable chest radiographs. We found that observers could confirm up to 90 of the reported findings in the thorax using video- printer images, when the original radiographs were of high quality. The number of verified findings was diminished when high spatial resolution was required (e.g. detection of a subtle pneumothorax) or when a low-contrast finding was located in the mediastinal area or below the diaphragm (e.g. nasogastric tubes).

To design a semi-automated program to measure the minimum tibiofemoral joint space width (JSW) of knee radiographs. Bilateral knee radiographs were obtained twice within a 2 week period from 34 asymptomatic research participants. Radiographicimages were analyzed to report both the variability of the image analysis program and the reproducibility of JSW measurements within a 2 week period. In addition, the results were compared with minimum JSW measurements read manually by an experienced musculoskeletal radiologist. The variability of the image analysis program was shown to be within one pixel. The results showed that reproducibility was better with the automated method. In addition, the manual method measured a greater minimum JSW than the automated method. There was no significant difference in between-day measurements. There was a significant difference reported between the automated and manual minimum JSW measurements. A novel semi-automated method for measurement of JSW has been developed. (orig.)

Recent advances in programming languages for graphics processing units (GPUs) provide developers with a convenient way of implementing applications which can be executed on the CPU and GPU interchangeably. GPUs are becoming relatively cheap, powerful, and widely available hardware components, which can be used to perform intensive calculations. The last decade of hardware performance developments shows that GPU-based computation is progressing significantly faster than CPU-based computation, particularly if one considers the execution of highly parallelisable algorithms. Future predictions illustrate that this trend is likely to continue. In this paper, we introduce a way of accelerating 2-D/3-D image registration by developing a hybrid system which executes on the CPU and utilizes the GPU for parallelizing the generation of digitally reconstructed radiographs (DRRs). Based on the advancements of the GPU over the CPU, it is timely to exploit the benefits of many-core GPU technology by developing algorithms for DRR generation. Although some previous work has investigated the rendering of DRRs using the GPU, this paper investigates approximations which reduce the computational overhead while still maintaining a quality consistent with that needed for 2-D/3-D registration with sufficient accuracy to be clinically acceptable in certain applications of radiation oncology. Furthermore, by comparing implementations of 2-D/3-D registration on the CPU and GPU, we investigate current performance and propose an optimal framework for PC implementations addressing the rigid registration problem. Using this framework, we are able to render DRR images from a 256×256×133 CT volume in ~24 ms using an NVidia GeForce 8800 GTX and in ~2 ms using NVidia GeForce GTX 580. In addition to applications requiring fast automatic patient setup, these levels of performance suggest image-guided radiation therapy at video frame rates is technically feasible using relatively low cost PC

To design a semi-automated program to measure minimum patellofemoral joint space width (JSW) using standing lateral view radiographs. Lateral patellofemoral knee radiographs were obtained from 35 asymptomatic subjects. The radiographs were analyzed to report both the repeatability of the image analysis program and the reproducibility of JSW measurements within a 2 week period. The results were also compared with manual measurements done by an experienced musculoskeletal radiologist. The image analysis program was shown to have an excellent coefficient of repeatability of 0.18 and 0.23 mm for intra- and inter-observer measurements respectively. The manual method measured a greater minimum JSW than the automated method. Reproducibility between days was comparable to other published results, but was less satisfactory for both manual and semi-automated measurements. The image analysis program had an inter-day coefficient of repeatability of 1.24 mm, which was lower than 1.66 mm for the manual method. A repeatable semi-automated method for measurement of the patellofemoral JSW from radiographs has been developed. The method is more accurate than manual measurements. However, the between-day reproducibility is higher than the intra-day reproducibility. Further investigation of the protocol for obtaining sequential lateral knee radiographs is needed in order to reduce the between-day variability. (orig.)

Conventional screen-film radiography does not display all regions of the thorax satisfactorily. Three chest radiographic techniques display both the lung and the mediastinum with good contrast. These techniques are asymmetric screen-film (ASF), digital storage phosphor (DSP), and digital selenium drum (DSD) imaging. ASF systems use two asymmetric screen-film combinations to produce a wide-latitude image of the thorax with good contrast in the lungs. In DSP systems, image data are acquired digitally with a wide dynamic range by using the optical output of a photostimulable phosphor plate; in DSD systems, the wide-range digitalimage data are acquired by using the electronic charge generated on a drum coated with a thin layer of amorphous selenium. The appearance of a DSP or DSD radiograph is then determined by user-selected image processing operations: tone scaling, spatial frequency processing, and dynamic range compensation. Digital chest radiographs processed with strong regional equalization provide both excellent contrast in the lungs and effective display of the mediastinum and chest wall. At visual comparison, the high lung contrast and good mediastinal, retrocardiac, and subdiaphragmatic detail provided by the DSD method distinguish it from the other two methods.

The use of computer simulated digital x-radiographs for optimisation purposes has become widespread in recent years. To make these optimisation investigations effective, it is vital simulated radiographs contain accurate anatomical and system noise. Computer algorithms that simulate radiographs based solely on the incident detector x-ray intensity (‘dose’) have been reported extensively in the literature. However, while it has been established for digital mammography that x-ray beam quality is an important factor when modelling noise in simulated images there are no such studies for diagnostic imaging of the chest, abdomen and pelvis. This study investigates the influence of beam quality on image noise in a digital radiography (DR) imaging system, and incorporates these effects into a digitally reconstructed radiograph (DRR) computer simulator. Image noise was measured on a real DR imaging system as a function of dose (absorbed energy) over a range of clinically relevant beam qualities. Simulated ‘absorbed energy’ and ‘beam quality’ DRRs were then created for each patient and tube voltage under investigation. Simulated noise images, corrected for dose and beam quality, were subsequently produced from the absorbed energy and beam quality DRRs, using the measured noise, absorbed energy and beam quality relationships. The noise images were superimposed onto the noiseless absorbed energy DRRs to create the final images. Signal-to-noise measurements in simulated chest, abdomen and spine images were within 10% of the corresponding measurements in real images. This compares favourably to our previous algorithm where images corrected for dose only were all within 20%.

In summary, it has been demonstrated by this study that the detection rate of definite large proximal surface caries (C2) on the digitalimages was good and the detection rate of the first stage caries (C1) was somewhat inferior to film based images. It has been demonstrated by this study and others that the detection of proximal surface caries by present clinical methodologies is still poor. Every effort should be made to develop new means to improve digitizing process.

1.1 This practice facilitates the interoperability of digital X-ray imaging equipment by specifying image data transfer and archival methods in commonly accepted terms. This document is intended to be used in conjunction with Practice E2339 on DigitalImaging and Communication in Nondestructive Evaluation (DICONDE). Practice E2339 defines an industrial adaptation of the NEMA Standards Publication titled DigitalImaging and Communications in Medicine (DICOM, see http://medical.nema.org), an international standard for image data acquisition, review, storage and archival storage. The goal of Practice E2339, commonly referred to as DICONDE, is to provide a standard that facilitates the display and analysis of NDE results on any system conforming to the DICONDE standard. Toward that end, Practice E2339 provides a data dictionary and a set of information modules that are applicable to all NDE modalities. This practice supplements Practice E2339 by providing information object definitions, information modules and a ...

Grid evaluation for a screen-film x-ray system has typically included independent measurement of the opposing contrast improvement factor and Bucky factor. Neither of these metrics, however, is appropriate when assessing grid performance in a digitalimaging environment. For digitalradiographic systems, the benefit of an anti-scatter grid is well characterized by the quantum signal-to-noise ratio improvement factor (K(SNR)) provided by the grid. The purpose of this work was to measure K(SNR) of prototype grids designed for use with digitalradiographic systems. The prototype grids had 5 mm tall lead septa, fiber interspace material, line rate N = 25 and 36 cm(-1) and ratio r = 15 and 21, respectively. The primary and scatter transmission properties of the grids were measured, and K(SNR) was evaluated over a phantom thickness range of 10-50 cm. To provide a comparison, the K(SNR) of similarly constructed N44r15 and N80r15 grids is also reported. K(SNR) of the prototype grids ranged from 1.4 for the 10 cm phantom to 2.4 for the 50 cm phantom. For the thickest phantom, the SNR improvement factor of the prototype grids was 18-83% higher than that of the N44r15 and N80r15 grids, respectively.

To develop an experimental method for measuring the effective detective quantum efficiency (eDQE) of digitalradiographicimaging systems and evaluate its use in select imaging systems. A geometric phantom emulating the attenuation and scatter properties of the adult human thorax was employed to assess eight imaging systems in a total of nine configurations. The noise power spectrum (NPS) was derived from images of the phantom acquired at three exposure levels spanning the operating range of the system. The modulation transfer function (MTF) was measured by using an edge device positioned at the anterior surface of the phantom. Scatter measurements were made by using a beam-stop technique. All measurements, including those of phantom attenuation and estimates of x-ray flux, were used to compute the eDQE. The MTF results showed notable degradation owing to focal spot blur. Scatter fractions ranged between 11% and 56%, depending on the system. The eDQE(0) results ranged from 1%-17%, indicating a reduction of up to one order of magnitude and different rank ordering and performance among systems, compared with that implied in reported conventional detective quantum efficiency results from the same systems. The eDQE method was easy to implement, yielded reproducible results, and provided a meaningful reflection of system performance by quantifying image quality in a clinically relevant context. The difference in the magnitude of the measured eDQE and the ideal eDQE of 100% provides a great opportunity for improving the image quality of radiographic and mammographic systems while reducing patient dose. RSNA, 2008

The purpose of this study was to examine the correlation between the basic imaging properties of two digitalradiographic X-ray systems with a direct conversion flat-panel detector and their image qualities, which were evaluated by the observer in hard copy and soft copy studies. The subjective image quality was evaluated and compared in terms of the low-contrast detectability and image sharpness in the two digitalradiographic X-ray systems. We applied the radiographs of a contrast detail phantom to the evaluation of low-contrast detectability and analyzed the contrast detail diagrams. Finally, low-contrast detectability was evaluated by the image quality figure (IQF) calculated from the contrast detail diagrams. Also, the subjective image sharpness of human dry bones of two systems was examined and evaluated by the normalized-rank method. The results indicated that System A tended to provide superior subjective image quality compared to System B in both observer studies. We also found high correlations between IQFs and basic imaging properties, such as the noise power spectrum (NPS) and the noise equivalent quantum (NEQ). In conclusion, the low-contrast detectability of the two digitalradiographic X-ray systems with a direct conversion flat-panel detector corresponded to the NPS and the NEQ in both outputs (soft copy and hard copy). On the other hand, the subjective image sharpness of human dry bones was affected by their noise properties.

This paper deals with the optimum radiographic condition in digitalradiographic systems. Radiographic conditions for chest and bone radiography with the computed radiographic (CR) system were reviewed. The effect of incident exposure on the detectability of various abnormalities including nodule, pneumothorax, asbestosis, fine pulmonary line and other abnormalities were also discussed. Radiographic conditions for radiography with portable X-ray unit and CR system were investigated at several institutions. Chest and abdominal examinations with the CR system were performed under the same exposure conditions as those of screen-film systems. However, large fluctuations in the radiographic condition were found by some technologists. (author).

Visualising volumetric medical images such as computed tomography and magnetic resonance imaging (MRI) on picture archiving and communication systems (PACS) clients is often achieved by image browsing in sagittal, coronal or axial views or three-dimensional (3D) rendering. This latter technique requires fine thresholding for MRI. On the other hand, computing virtual radiographimages, also referred to as digitally reconstructed radiographs (DRR), provides in a single two-dimensional (2D) image a complete overview of the 3D data. It appears therefore as a powerful alternative for MRI visualisation and preview in PACS. This study describes a method to compute DRR from T1-weighted MRI. After segmentation of the background, a histogram distribution analysis is performed and each foreground MRI voxel is labeled as one of three tissues: cortical bone, also known as principal absorber of the X-rays, muscle and fat. An intensity level is attributed to each voxel according to the Hounsfield scale, linearly related to the X-ray attenuation coefficient. Each DRR pixel is computed as the accumulation of the new intensities of the MRI dataset along the corresponding X-ray. The method has been tested on 16 T1-weighted MRI sets. Anterior-posterior and lateral DRR have been computed with reasonable qualities and avoiding any manual tissue segmentations. This proof-of-concept holds for research application for use in clinical PACS.

Paper copies of digitalradiographs printed with the continuous ink-jet technique have proved to be of a high enough quality for demonstration purposes. We present a study on the image quality of ink-jet printed paper copies of digital chest radiographs, based on receiver operating characteristic (ROC) analysis. Eighty-three digitalradiographs of a chest phantom with simulated tumors in the mediastinum and right lung, derived from a computed radiography (CR) system were presented in two series of hard copies as ink-jet printed paper copies and as laser recorded film. The images, with a matrix of 1,760 x 2,140 pixels, were printed with a spatial resolution of 10 pixels/mm in the CR film recorder as well as in the ink-jet printer. On film, every image was recorded in two versions, one optimized for the mediastinum and one for the lungs. On paper, only one image was printed; this constituted an effort to optimize both the mediastinum and the lungs. The ink-jet printed images, printed on a matt coated paper, were viewed as on-sight images with reflected light. The examinations were reviewed by six radiologists, and ROC curves were constructed. No significant difference was found between the performance of film and that of ink-jet paper prints. Because the cost for a paper copy is only a tenth of that of film, remarkable cost reductions can be achieved by using the ink jet technique instead. Our results show that further quality studies of ink-jet printed images are worthwhile.

High speed x-ray imaging can be an important tool for observing internal processes in a wide range of applications. In this paper we describe preliminary implementation of a system having the eventual goal of observing the internal dynamics of bone and joint reactions during loading. Two Los Alamos National Laboratory (LANL) gated and image intensified camera systems were used to record images from an x-ray image convertor tube to demonstrate the potential of high frame-rate digitalradiographic videography in the analysis of bone and joint dynamics of the human body. Preliminary experiments were done at LANL to test the systems. Initial high frame-rate imaging (from 500 to 1000 frames/s) of a swinging pendulum mounted to the face of an X-ray image convertor tube demonstrated high contrast response and baseline sensitivity. The systems were then evaluated at the Motion Analysis Laboratory of Henry Ford Health Systems Bone and Joint Center. Imaging of a 9 inch acrylic disk with embedded lead markers rotating at approximately 1000 RPM, demonstrated the system response to a high velocity/high contrast target. By gating the P-20 phosphor image from the X-ray image convertor with a second image intensifier (II) and using a 100-microsecond wide optical gate through the second II, enough prompt light decay from the x-ray image convertor phosphor had taken place to achieve reduction of most of the motion blurring. Measurement of the marker velocity was made by using video frames acquired at 500 frames/s. The data obtained from both experiments successfully demonstrated the feasibility of the technique. Several key areas for improvement are discussed along with salient test results and experiment details.

The application of digitalimage processing to mass screening for breast cancer is demonstrated in the context of adaptive spatial filtering. Experimental results for feature extraction by texture analysis and grey level thresholding reveal there is significant potential for computer-aided mass screening as an adjunct to radiological examination. Digitalimage processing can improve the visibility of image features, such as neoplasms or tumours, providing also speed and automation of inspection, whilst saving the radiologist time which is otherwise spent on checking clear samples (which represent the majority of screening cases). (author)

A contrast detail analysis was performed to compare perception of low-contrast details on X-ray images derived from digital storage phosphor radiography and from a flat panel detector system based on a cesium iodide/amorphous silicon matrix. The CDRAD 2.0 phantom was used to perform a comparative contrast detail analysis of a clinical storage phosphor radiography system and an indirect type digital flat panel detector unit. Images were acquired at exposure levels comparable to film speeds of 50/100/200/400 and 800. Four observers evaluated a total of 50 films with respect to the threshold contrast for each detail size. The numbers of correctly identified objects were determined for all image subsets. The overall results show that low-contrast detail perception with digital flat panel detector images is better than with state of the art storage phosphor screens. This is especially true for the low-exposure setting, where a nearly 10% higher correct observation ratio is reached. Given its high detective quantum efficiency the digital flat panel technology based on the cesium iodide scintillator/amorphous silicon matrix is best suited for detection of low-contrast detail structures, which shows its high potential for clinical imaging.

Computed Radiography (CR) has become a major digitalimaging modality in a modern radiological department. CR system changes workflow from the conventional way of using film/screen by employing photostimulable phosphor plate technology. This results in the changing perspectives of technical, artefacts and quality control issues in radiology departments. Guidelines for better image quality in digital medical enterprise include professional guidelines for users and the quality control programme specifically designed to serve the best quality of clinical images. Radiographers who understand technological shift of the CR from conventional method can employ optimization of CR images. Proper anatomic collimation and exposure techniques for each radiographic projection are crucial steps in producing quality digitalimages. Matching image processing with specific anatomy is also important factor that radiographers should realise. Successful shift from conventional to fully digitised radiology department requires skilful radiographers who utilise the technology and a successful quality control program from teamwork in the department.

The use of computers in dentistry is becoming common as a practice tool for a diverse number of tasks, including the storage and enhancement of intra-oral radiographs. Several systems of digital radiography are available to produce a digitalimage including irradiation of a charged-couple device and scanning conventional radiographs. This study compared various digitalimages of scanned periapical radiographs with the original radiographs to determine whether the digitizedimages offered any advantage when viewing small files at the radiographic apex. Twenty extracted permanent molar teeth were prepared by gaining straight line access to the root canals and a ISO size 06 K-file was introduced into one of the canals until the tip was flush with the apical foramen. Using a standardized technique, radiographs were taken of the teeth using E-speed film. The radiographs were scanned and five digitalimages: original, enhanced, negative to positive conversion, zoom and zoom of negative to positive were produced. Three evaluators compared each of the images with the radiograph for clarity of the endodontic file in relation to the radiographic apex. Results were analysed using the Wilcoxon signed rank test and the Kappa (kappa) test was used to measure the level of agreement between the three evaluators. The results revealed that all the digitalimages produced by this scanner were inferior to the radiograph (P < 0.001) and that there was high agreement between evaluators.

Full Text Available Panoramic radiography is a unique and a very useful extraoral film technique that allows the dentist to view the entire dentition and related structures, from condyle to condyle, on one film. Capturing a wide range of structures on a single film grounds the odds of errors in the digital panoramic radiographs. Improper positioning of the patient complicates it more, reducing the diagnostic usefulness of these radiographs. Wide knowledge about the common positioning errors and the ways to rectify it benefits the dentists in interpretation and diagnosis. Aim: This study is aimed at analyzing the 10 common positional errors (anteriorly positioned, posteriorly positioned, head tilted upwards, head tilted downwards, head twisted to one side, head tipped, overlapping of spine in lower anterior region, tongue not placed close to palate, patient movement, and ghost images in 200 digital panoramic radiographs selected randomly. Materials and Methods: Two hundred digital panoramic radiographicimages of the patients above 6 years of age were selected randomly from the stored data in the system, projected on the white screen, and studied. The radiographs were analyzed by two oral medicine and radiology specialists, by recording separately, and then the results were analyzed. Results: The most common error was failure to place the tongue close to the palate, which leads to the presence of radiolucent airspace obscuring the roots of the maxillary teeth.

Over the past decade, many different imaging techniques have been proposed and shown to be capable of producing NMR images. Four Gd-based contrast agents for intravenous administration are now being used and tested nationally and internationally. Two of these are ionic (magnevist , dotarem) and two are non-ionic (omni scan, prohance). This article review information about MR imaging contrast agents, their types, chemical components, administration and reaction, to enable MR user to be aware of the basic pharmacokinetics, side effects and the potential for adverse events.

The acquired immunodeficiency syndrome (AIDS) has impacted the civilized world like no other disease. This research aimed to discuss some of the main aids-related complications and their detection by radiology tests, specifically central nervous system and musculoskeletal system disorders. The objectives are: to show specific characteristics of various diseases of HIV patient, to analyze the effect of pathology in patients by radiology, to enhance the knowledge of technologists in aids imaging and to improve communication skills between patient and radiology technologists.

Full Text Available Background: The styloid process is an anatomical structure, whose clinical importance is not well understood. Proper clinical and radiographic evaluation can detect an elongated styloid process and calcification of the stylohyoid ligament. It has been reported that 2 - 28% of the general population show radiographic evidence of mineralization of a portion of the stylohyoid chain. The elongated styloid process may be symptomatic in many cases. Panoramic radiography is the best imaging modality to view the styloid process bilaterally. Aim: To assess the styloid process on digital panoramic radiographs. Materials and Methods: The study was conducted on 500 digital panoramic radiographs available in the archives of our department as soft copies. These radiographs were taken using a digital panoramic system. The radiographic length of the styloid process was measured on both sides using the measurement toolbars on the accompanying analysis software. For statistical analysis we used the unpaired t test, Chi-square test, and one-way ANOVA test, as necessary. Results: The average length of the left styloid was 25.41 ± 6.32 mm and that of the right styloid was 25.53 ± 6.62 mm. The length of both styloids increased with age and males had longer styloids than females. Elongated styloids were present in 19.4% of the panoramic radiographs. Langlais type I elongated styloids and a partial calcification pattern were more common than others. Conclusion: Panoramic radiography is useful for detection of an elongated styloid process and / or ossification of the stylohyoid ligament in patients with or without symptoms, and helps avoid a misdiagnosis of tonsillar pain or pain of dental, pharyngeal, or muscular origin.

Corals are widely used for environmental and climatic changes assessment as their skeletal growth is influenced by the surrounding environment. Variations in skeletal density are sensitive to environmental variations (water temperature, nutrients concentration etc.). Digitized X-radiographs have been used for coral skeleton density measurements since the 1980s. However, the shape of the X-ray beam emitted during the irradiation process is strongly distorted due to spherical spreading (inverse square law) and heel effect. Consequently, the X-ray intensity intersecting the surface of the sensitive film or the electronic sensor (e.g. PSL plate) is heterogeneous. These heterogeneities are characterized by an asymmetrical concentric pattern of decreasing intensity from the center to the edges of the X-radiographs. It commonly generates an error on density measurements that may reach up to 40%. This is twice as much as the seasonal density variations that are usually found in corals. Until now, extra X-ray images or aluminum standards were used to correct X-radiographs. Such corrective methods may be constraining when working with a high number of coral samples. We present an inexpensive, straightforward, and accurate method to correct strong heterogeneities of X-ray irradiation that affect X-ray images. The method relies on the relation between optical density (OD) and skeletal density; it is non-destructive, and provides high-resolution measurements. Our method was applied to measure density variations on Caribbean reef-building coral Siderastrea siderea from Costa Rica. The basic assumption is that the X-radiograph background, i.e., areas without objects, records the asymmetrical concentric pattern of X-ray intensity. A full image of this pattern was created with a natural neighbor interpolation. The resulting modeled image was then subtracted from the original X-ray image, permitting thus a reliable OD measurement directly on the corrected X-ray image. This Digital

The requirements for the rapid display of radiographicimages exceed the capabilities of widely available display, computer, and communications technologies. Computed radiography captures data with a resolution of about four megapixels. Large-format displays are available that can present over four megapixels. One megapixel displays are practical for use in combination with large-format displays and in areas where the viewing task does not require primary diagnosis. This paper describes an electronic radiology system that approximates the highest quality systems, but through the use of several interesting techniques allows the possibility of its widespread installation throughout hospitals. The techniques used can be grouped under three major system concepts: a local, high-speed image server, one or more physician's workstations each with one or more high-performance auxiliary displays specialized to the radiology viewing task, and dedicated, high-speed communication links between the server and the displays. This approach is enhanced by the use of a progressive transmission scheme to decrease the latency for viewing four megapixel images. The system includes an image server with storage for over 600 4-megapixel images and a high-speed link. A subsampled megapixel image is fetched from disk and transmitted to the display in about one second followed by the full resolution 4-megapixel image in about 2.5 seconds. Other system components include a megapixel display with a 6-megapixel display memory space and frame-rate update of image roam, zoom, and contrast. Plans for clinical use are presented.

Full Text Available Computer-aided detection systems aim at the automatic detection of diseases using different medical imaging modalities. In this paper, a novel approach to detecting normality/pathology in digital chest radiographs is proposed. The problem tackled is complicated since it is not focused on particular diseases but anything that differs from what is considered as normality. First, the areas of interest of the chest are found using template matching on the images. Then, a texture descriptor called local binary patterns (LBP is computed for those areas. After that, LBP histograms are applied in a classifier algorithm, which produces the final normality/pathology decision. Our experimental results show the feasibility of the proposal, with success rates above 87% in the best cases. Moreover, our technique is able to locate the possible areas of pathology in nonnormal radiographs. Strengths and limitations of the proposed approach are described in the Conclusions.

Digitizingimages with low cost off-the-shelf technology arises as an alternative to storage films in developing countries. The objective of this work is to determine a low-cost method to digitize Rx films for educative and remote-consult purposes. To this aim, different ways of digitizing were compared against conventional methods to determine the feasibility to have a simple-low cost method that is quality independent from facilities and operator. Different images from digital photo cameras and scanners (with or without transparency adapter at different resolutions and color depth) were analyzed. We present preliminary results for digitizing Rx films with a fast and simple inexpensive system that capture quality images, and optimal sizes for storage in basic PCs in hospitals, with the possibility of asking for a second opinion via e-mail or through a web-based service. It must be noted that in many cases the only way of communication is via dial-up telephone line.

Digitizingimages with low cost off-the-shelf technology arises as an alternative to storage films in developing countries. The objective of this work is to determine a low-cost method to digitize Rx films for educative and remote-consult purposes. To this aim, different ways of digitizing were compared against conventional methods to determine the feasibility to have a simple-low cost method that is quality independent from facilities and operator. Different images from digital photo cameras and scanners (with or without transparency adapter at different resolutions and color depth) were analyzed. We present preliminary results for digitizing Rx films with a fast and simple inexpensive system that capture quality images, and optimal sizes for storage in basic PCs in hospitals, with the possibility of asking for a second opinion via e-mail or through a web-based service. It must be noted that in many cases the only way of communication is via dial-up telephone line.

The increasing number of digitalimaging modalities results in data volumes of several Tera Bytes per year that must be transferred and archived in a common-sized hospital. Hence, data compression is an important issue for picture archiving and communication systems (PACS). The effect of lossy image compression is frequently analyzed with respect to images from a certain modality supporting a certain diagnosis. However, novel compression schemes have been developed recently allowing efficient but lossless compression. In this study, we compare the lossless compression schemes embedded in the tagged image file format (TIFF), graphics interchange format (GIF), and Joint Photographic Experts Group (JPEG 2000 II) with the Borrows-Wheeler compression algorithm (BWCA) with respect to image content and origin. Repeated measures ANOVA was based on 1.200 images in total. Statistically significant effects (p radiographs of the head, while the lowest factor of 1,05 (7.587 bpp) resulted from the TIFF packbits algorithm applied to pelvis images captured digitally. Over all, the BWCA is slightly but significantly more effective than JPEG 2000. Both compression schemes reduce the required bits per pixel (bpp) below 3. Also, secondarily digitizedimages are more compressible than the directly digital ones. Interestingly, JPEG outperforms BWCA for directly digitalimages regardless of image content, while BWCA performs better than JPEG on secondarily digitizedradiographs. In conclusion, efficient lossless image compression schemes are available for PACS.

A prototype system for digital panoramic imaging of the maxillofacial complex has been developed. In this system x-ray film is replaced by an electronic sensor that delivers the image information to a computer for storage in digital format. The images, which are similar to conventional panoramic radiographs, are displayed on a high-resolution video monitor and may be stored on optical disk for future use. Hard-copy output is also available. The present prototype system has been installed on an Orthopantomograph model OP10 panoramic x-ray machine is programmed for operation with this machine, but in principle the system can be installed on any such device. The system may be incorporated into the design of future panoramic x-ray systems or may be used to retrofit panoramic x-ray systems now using photographic film to record the radiographicimage. Greater sensitivity of electronic sensors should make possible a reduction of x-ray dose to the patient, compared with film-based systems.

...: To assess the usefulness of panoramic radiographs as a tool to estimate the growth and to ascertain the importance of tooth calcification stages as an indicator of maturity by using digital panoramic radiographs. Methods...

In dentistry, Radio Visio Graphy was introduced as a first electronic dental x-ray imaging modality in 1989. Thereafter, many types of direct digitalradiographic systems have been produced in the last decade. They are based either on charge-coupled device (CCD) or on storage phosphor technology. In addition, new types of digitalradiographic system using amorphous selenium, image intensifier etc. are under development. Advantages of digitalradiographic system are elimination of chemical processing, reduction in radiation dose, image processing, computer storage, electronic transfer of images and so on. Image processing includes image enhancement, image reconstruction, digital subtraction, etc. Especially digital subtraction and reconstruction can be applied in many aspects of clinical practice and research. Electronic transfer of images enables filmless dental hospital and teleradiology/teledentistry system. Since the first image management and communications system (IMACS) for dentomaxillofacial radiology was reported in 1992, IMACS in dental hospital has been increasing. Meanwhile, researches about computer-assisted diagnosis, such as structural analysis of bone trabecular patterns of mandible, feature extraction, automated identification of normal landmarks on cephalometric radiograph and automated image analysis for caries or periodontitis, have been performed actively in the last decade. Further developments in digitalradiographicimaging modalities, image transmission system, imaging processing and automated analysis software will change the traditional clinical dental practice in the 21st century.

The aim of this study was to investigate the use and acceptance of digitalradiographic examinations by Brazilian dental practitioners in daily practice and to evaluate the advances that have occurred over the past 5 years. Dental practitioners enrolled in extension courses at the Piracicaba Dental School, University of Campinas, Brazil, responded to a self-administered questionnaire in the years 2011 and 2015. They were asked about sociodemographic factors and their knowledge and use of digitalradiographic examinations. Descriptive analysis was performed, as well as the chi-square and Fisher exact tests, with a significance level of 5% (α=0.05). A total of 181 participants responded to the questionnaire in the years 2011 and 2015. Most of the respondents worked in private practice, had graduated within the last 5 years, and were between 20 and 30 years old. In 2011, 55.6% of respondents reported having ever used digitalradiographic examinations, while in 2015 this number increased significantly to 85.4% (pimages. Moreover, 21.4% of respondents reported having used digitalradiographic examinations for more than 3 years. A significant increase in use of intraoral digital radiography (p=0.0316) was observed in 2015. In both years, image quality and high cost were indicated, respectively, as the main advantage and disadvantage of digitalradiographic examinations. This study showed that digital radiology has become more common in Brazil over the past 5 years. Most of the Brazilian dental practitioners evaluated in 2015 used digitalradiographic examinations.

In this paper we describe a system for the digitization, display, and storage of radiographicimages. The system was set up to support a project to assess the clinical impact of matrix size on teleradiology, defined for our purposes as the electronic recording and transmission of radiographs. The system consists of two separate facilities, one for imagedigitizing and the other for image display, interpretation, and archiving. The imagedigitizing laboratory uses a solid state scanner interfaced to a dedicated, general-purpose minicomputer. The display facility consists of a general-purpose, multi-user minicomputer with large main memory and disk capacity and a 1280 by 1024 display subsystem with three separate image memories. The two facilities communicate via magnetic tape. This paper documents the characterization of the image data base used for the project, the design and operational features of the two facilities, technical problems encountered in the digitizing and display of radiographs, and some logistical and managerial considerations involved in generating and maintaining a large digitalimage archive. Since many of the functions of the system we have set up are common to picture archiving and communication systems, we have, where possible, compared the performance of the system we have developed with the requirements that would have to be satisfied by a system intended for clinical use. We leave for future reports the discussion of the conduct of the image reading experiments and the results of those experiments.

1.1 The digital reference images provided in the adjunct to this standard illustrate various types and degrees of discontinuities occurring in titanium castings. Use of this standard for the specification or grading of castings requires procurement of the adjunct digital reference images, which illustrate the discontinuity types and severity levels. They are intended to provide the following: 1.1.1 A guide enabling recognition of titanium casting discontinuities and their differentiation both as to type and degree through digitalradiographic examination. 1.1.2 Example digitalradiographic illustrations of discontinuities and a nomenclature for reference in acceptance standards, specifications and drawings. 1.2 The digital reference images consist of seventeen digital files each illustrating eight grades of increasing severity. The files illustrate seven common discontinuity types representing casting sections up to 1-in. (25.4-mm). 1.3 The reference radiographs were developed for casting sections up to 1...

Up till now no reliable radiographicimage quality standards exist for neutron radiography of nuclear reactor fuel. Under the Euratoro Neutron Radiography Working Group (NRWG) Test Program neutron radiographs were produced at different neutron radiography facilities within the European Community...... of a calibration fuel pin. The radiographs were made by the direct, transfer and tracketch methods using different film recording materials. These neutron radiographs of the calibration fuel pin were used for the assessement of radiographicimage quality. This was done by visual examination of the radiographs...

Inspection of turbine blades has always been a big challenge. Any irregularities in the blade have a huge impact on the gas turbine, so these blades have to be manufactured and inspected in the most sophisticated way possible. The evolution of digitalradiographic technology took a leap forward to

Inspection of turbine blades has always been a big challenge. Any irregularities in the blade have a huge impact on the gas turbine, so these blades have to be manufactured and inspected in the most sophisticated way possible. The evolution of digitalradiographic technology took a leap forward to s

Radiographs are important tools to evaluate structural changes in many Joint diseases. In the case of haemophilic arthropathy (HA), the Pettersson score is widely used. The rising of digital radiography enables evaluation of these changes in a more quantitative and detailed manner, potentially impro

To investigate the reproducibilities and compare the measurements in digital and MDCT-synthesized cephalometric radiograph, and to investigate the effect of head position on the measurement during imaging with MDCT. Twenty-two dry skulls (combined with mandible) were used in this study. Conventional digital cephalometric radiograph was taken in standard position, and MDCT was taken in standard position and two rotated position (10 .deg. C left rotation and 10 .deg. C right tilting). MDCT data were imported in OnDemand and lateral cephalometric radiograph were synthesized from 3D virtual models. Two types of rotated MDCT data were synthesized with default mode and with corrected mode using both ear rods. For all six images, sixteen angular and eleven linear measurements were made in V-Ceph three times. Reproducibility of measurements was assessed using repeated measures ANOVA and ICC. Linear and angular measurements were compared between digital and five MDCTsynthesized images by Student t-test. All measurements in six types of cephalometric radiograph were not statistically different under ICC examination. Measurements were not different between digital and MDCT-synthesized images (P> .05). Measurements in MDCT-synthesized image in 10 .deg. C left rotation or 10 .deg. C right tilting position showed possibility of difference from digitalimage in some measurements, and possibility of improvement via realignment of head position using both ear rods. MDCT-synthesized cephalometric radiograph can substitute conventional cephalometric radiograph. The error on head position during imaging with MDCT have possibility that can produce measurement errors with MDCT-synthesized image, and these position error can be corrected by realignment of the head position using both ear rods.

Purpose: To describe the magnetic resonance imaging (MRI) and radiographic findings of five patients with seal finger. Material and Methods: The MR images and radiographs of five patients with seal finger were retrospectively evaluated. MRI was performed on four patients in the subacute phase, and follow-up imaging was done on one of them at 5 months. One patient had MRI only at a later stage 5 years after onset. Radiographs were taken three times in the subacute phase and once at a later stage. One patient had had seal finger in another finger previously. Results: Short-tau inversion-recovery (STIR) sequence showed extensive subcutaneous soft tissue edema in all four patients in the subacute phase and tenosynovitis of the flexion tendons in two cases. Three patients had edema in 2-3 phalanges, and effusion in the distal interphalangeal (DIP) joint was seen in one case. At the later stage, no signal pathology in soft tissues or bones was seen in STIR images. In the subacute phase, radiographs showed digital soft-tissue swelling in three patients, and one patient had a narrowed DIP joint, periarticular osteoporosis, and a periosteal reaction. At the later stage, flexion contracture of the finger was seen. Conclusion: In addition to soft-tissue infection, seal finger causes bone marrow edema, tenosynovitis, and effusion in the interphalangeal joints visible as increased signal intensity in STIR images. Radiographs reveal periarticular osteoporosis with loss of cartilage in the subacute phase and flexion contracture at the later stage. MRI (STIR) allows more precise delineation of the inflammatory process compared to radiography.

Calculating digitally reconstructed radiographs (DRRs)is an important step in intensity-based fluoroscopy-to-CT image registration methods. Unfortunately, the standard techniques to generate DRRs involve ray casting and run in time O(n3),where we assume that n is approximately the size (in voxels) of one side of the DRR as well as one side of the CT volume. Because of this, generation of DRRs is typically the rate-limiting step in the execution time of intensity-based fluoroscopy-to-CT registration algorithms. We address this issue by extending light field rendering techniques from the computer graphics community to generate DRRs instead of conventional rendered images. Using light fields allows most of the computation to be performed in a preprocessing step;after this precomputation step, very accurate DRRs can be generated in time O(n2). Using a light field generated from 1,024 DRRs of resolution 256×256, we can create new DRRs that appear visually identical to ones generated by conventional ray casting. Importantly, the DRRs generated using the light field are computed over 300 times faster than DRRs generated using conventional ray casting(50 vs.17,000 ms on a PC with a 2 GHz Intel Pentium 4 processor).

A digitalradiographic system using the technology of laser stimulated luminescence has been utilized for the evaluation of scoliosis at reduced exposure levels. A total of 412 examinations have been performed on children with scoliosis. Diagnostic images were produced at significantly reduced radiation exposures when compared to standard radiographic techniques. Exposure reductions of 92% to 95% were consistently achieved. Since the potential for multiple examinations and considerable radiation exposure in this patient population is high, this is a significant application in the developing technology of digital radiography. (orig.).

While the quantitative nature of digital fluroscopic and digitalradiographicimaging would seem to make possible many radiotherapeutic applications, significant problems must first be solved. The purpose of this study is to examine the potential benefits of digitalimaging in radiation therapy, identify what problems must be solved to attain these benefits, and attempt to make some assessment as to the relative merits of developing such technologies. Among the potential benefits are ability to do contrast-subtraction studies for tumor and/or normal structure localization and portal placement, digital simulation of portal placement and treatment delivery, spatial localization and digitization of inhomogeneity boundaries, spatial localization and digitization of brachytherapy sources, and quantitative inhomogeneity acquisition for dosimetry calculations. Significant problems which must be solved include image receptor size limitations, image acquisition geometry related spatial distortion, three dimensional region calculation from limited views, and physical interpretation of digitalimage grey levels. Maximal benefits of digitalimaging in radiation oncology is likely to be obtained by the development of large area image receptors for use in therapy simulators with direct data link to a combined image-analysis/treatment planning computer.

Full Text Available INTRODUCTION: A successful endodontic therapy depends on the linear measurements obtained by means of radiographs taken during odontometry and also on the application of the established working length up to the final obturation. OBJECTIVE: The aim of this study was to compare the precision of the linear measurement obtained by means of conventional radiographs and indirect digitalimages evaluated by the Digora 1.5 software during the different stages of endodontic treatment, as well as to evaluate the tools available on this software. METHODS: A total of 160 radiographs of single-rooted teeth were obtained from files, which were analysed and divided in 4 groups comprising odontometry, cone fit, condensation and the final obturation. Analyses of the conventional radiographs and digitizedimages were performed by five previuosly calibrated examiners. RESULTS: A high level of inter and intra-examiner agreement was observed through application of the Kendall coefficient and the correlation index, respectively. In relation to the results of linear measurement, the two-way variance analyses and the Tukey test revealed that, concerning the method, a statistically significant decrease was observed on the measurement obtained through the digital method when compared to the conventional radiograph (pA radiologia digital tem sido amplamente difundida na odontologia, especialmente na endodontia. O sucesso do tratamento endodôntico depende das medidas lineares obtidas a partir de radiografias tomadas durante a odontometria, e do seguimento do comprimento de trabalho determinado até a obturação final. Este trabalho objetivou comparar a precisão das medidas lineares obtidas em radiografias convencionais com as imagens digitais indiretas avaliadas pelo programa Digora 1.5, durante as diferentes fases do tratamento endodôntico, bem como avaliar as ferramentas disponíveis neste programa. Foram analisadas 160 radiografias de dentes unirradiculares, dos

The calculation of Cardiothoracic Ratio (CTR) in digital chest radiographs would be useful for cardiac anomaly assessment and heart enlargement related disease indication. The purpose of this study was to develop and evaluate a fully automated scheme for calculation of CTR in digital chest radiographs. Our automated method consisted of three steps, i.e., lung region localization, lung segmentation, and CTR calculation. We manually annotated the lung boundary with 84 points in 100 digital chest radiographs, and calculated an average lung model for the subsequent work. Firstly, in order to localize the lung region, generalized Hough transform was employed to identify the upper, lower, and outer boundaries of lung by use of Sobel gradient information. The average lung model was aligned to the localized lung region to obtain the initial lung outline. Secondly, we separately applied dynamic programming method to detect the upper, lower, outer and inner boundaries of lungs, and then linked the four boundaries to segment the lungs. Based on the identified outer boundaries of left lung and right lung, we corrected the center and the declination of the original radiography. Finally, CTR was calculated as a ratio of the transverse diameter of the heart to the internal diameter of the chest, based on the segmented lungs. The preliminary results on 106 digital chest radiographs showed that the proposed method could obtain accurate segmentation of lung based on subjective observation, and achieved sensitivity of 88.9% (40 of 45 abnormalities), and specificity of 100% (i.e. 61 of 61 normal) for the identification of heart enlargements.

As typical for the study of the vapor explosions, the qualitative and quantitative understanding of the phenomena requires visualization of both material and interface dynamics. A new approach to multi-fluid multiphase visualization is presented with the focus on the development of a synchronized high-speed visualization by digital cinematography and X-ray radiography. The developed system, named SHARP (simultaneous high-speed acquisition of X-ray radiography and photography), and its image processing methodology, directed to an image synchronization procedure and a separate quantification of vapor and molten material dynamics, is presented in this paper. Furthermore, we exploit an intrinsic property of the X-ray radiation, namely the differences in linear mass attenuation coefficients over the beam path through a multi-component system, to characterize the evolution of molten material distribution. Analysis of the data obtained by the SHARP system and image processing procedure developed granted new insights into the physics of the vapor explosion phenomena, as well as, quantitative information of the associated dynamic micro-interactions. (author)

Full Text Available Digitalradiographs need additional metadata in order to be accurate when being converted to analog media. Resolution is a major reason of failures in proper printing or digitizing the images. This letter shortly explains the overlooked pitfalls of digital radiography and photography in dental practice, and briefly instructs the reader how to avoid or rectify common problems associated with resolution calibration of digitalradiographs.

Full Text Available Digitalradiographs need additional metadata in order to be accurate when being converted to analog media. Resolution is a major reason of failures in proper printing or digitizing the images. This letter shortly explains the overlooked pitfalls of digital radiography and photography in dental practice, and briefly instructs the reader how to avoid or rectify common problems associated with resolution calibration of digitalradiographs.

Digitalradiographs need additional metadata in order to be accurate when being converted to analog media. Resolution is a major reason of failures in proper printing or digitizing the images. This letter shortly explains the overlooked pitfalls of digital radiography and photography in dental practice, and briefly instructs the reader how to avoid or rectify common problems associated with resolution calibration of digitalradiographs. PMID:25469352

The purpose of digitalimage scrambling is to transforn a given digitalimage into a rather scrambled one so as to make it difficult for other people to find out the true meaning of the scrambled image. This paper comes up with a certain number of approaches to scrambling digitalimages, which, when thus processed, cannot be reconstructed in a common way. As a result, the original image is enc yrypted and protected.

The bedside chest images obtained with conventional radiology and with "on line" and "off line" digital modalities were compared to evaluate the respective capabilities in visualizing chest anatomical structures. Seventy patients were submitted to bedside chest examinations with a portable unit; both a conventional film and a digital system (PCR Graphics 1, Philips) with photostimulable phosphor imaging plate were fitted in the radiographic cassette. The former was digitized using an "off line" laser beam unit (FD 2000, Dupont); the latter was subsequently postprocessed by modifying contrast, optical density and spatial frequencies. Thus, 4 different viewing modalities were obtained for each examination: a) conventional radiography; b) standard digital radiography; c) postprocessed digital radiography; d) digitized conventional radiography. Detectability rates of chest anatomical structures were analyzed by 4 independent radiologists on the different images and expressed by a score 1-4. The values were always higher with digital modalities than with the conventional one and the differences were statistically significant (Student's t-test modified by Bonferroni). In particular, the greatest difference was found between c) and a) in retrocardiac lung parenchyma and in skeletal structures, in favour of c). Concerning the comparative adequacy of the various digital modalities, higher detectability rates of chest anatomical structures were obtained with c), but also with b), than with d).

Edge detecting techniques applied to radiographicdigitalimages are discussed. Some algorithms have been implemented and the results are displayed to enhance boundary or hide details. An algorithm applied in a pre processed image with contrast enhanced is proposed and the results are discussed 5 refs., 4 figs.

This study compares the intra- and interobserver variance of Cobb angle measurements of primary and secondary curves on digitalradiographs versus traditional radiographs. Four orthopaedic surgeons of varying experience measured the Cobb angles from a standard posteroanterior thoracolumbar scoliosis radiograph (25 digital, 25 traditional) on two occasions 2 weeks apart. The intra- and interobserver variances were calculated and compared for major versus minor curves and the digital versus traditional radiographs. There was no statistical difference in the mean error index, the variability in choosing the end vertebra on successive measurements, between the digital and traditional groups. Similarly, there was no significant difference in the intraobserver or interobserver variance between the digital and traditional groups. Digitalradiographs are comparable to the use of traditional radiographs for following patients with adolescent idiopathic scoliosis. Furthermore, increasing years of experience appears to result in fewer errors and more consistency using the Cobb method.

Full Text Available This work introduces a new way for data visualization. Its name is Digital Application name' Image. Normal digitalimage is created by digital camera or digital scanner but digital application name image is created by measurements of monitoring data. This work uses the data which is measured by radiation monitoring station and classifies it using fuzzy logic rules to create digital radiation image. The main unique advantage of digital radiation image is that it expresses thousands of measurements in a very clear form through only one picture while the maximum number of measurements does not exceed 100 with other conventional visualization methods. This feature gives a facility to view one year of all recorded measurements in only one photo. This picture helps the user to observe the behavior of thousands of measurements in few minutes instead of spending few hours for reviewing hundreds of charts for the same measurements.

Full Text Available Recent development in image processing allows us to apply it in different domains. Radiography image of weld joint is one area where image processing techniques can be applied. It can be used to identify the quality of the weld joint. For this the image has to be stored and processed later in the labs. In order to optimize the use of disk space compression is required. The aim of this study is to find a suitable and efficient lossless compression technique for radiographic weld images. Image compression is a technique by which the amount of data required to represent information is reduced. Hence image compression is effectively carried out by removing the redundant data. This study compares different ways of compressing the radiography images using combinations of different lossless compression techniques like RLE, Huffman.

ProRad is a computer program that is used to generate synthetic images of proton (or other charged particles) radiographs. The proton radiographs arc images that arc obtained by sending energetic protons (or electrons or positrons, for example) through 11 plasma where electric and/or magnetic fields alter the particles trajectory, Dnd the variations me imaged on RC film, image plate, or equivalent

Full Text Available INTRODUCTION : With the interest in anticipating access to the result of intraoral radiography, the radiographic processing is frequently neglected, compromising image quality. OBJECTIVE : The aim of this study was to evaluate the influence of interrupting the fixation process on the radiographic contrast and base-plus-fog density (BPFD in three brands of periapical films. MATERIAL AND METHOD : Ninety radiographs were taken of an aluminum stepwedge and a lead plate for each brand, and they were divided according to the time of initial immersion in the fixative in: control group (without interrupting the fixing, 5, 10, 20, 30 and 40 seconds. During processing, films had the fixing stage stopped and were exposed to a negatoscope for 1 minute, then the fixation time of 10 minutes was completed. The radiographs were digitized and exported to Image Tool 3.0.software. RESULT : Kodak(r film showed no statistically significant differences between groups, while Agfa(r film presented difference in BPFD compared with Group 5 seconds, and Dentix(r film showed statistical difference in all groups in comparison with the control group. CONCLUSION : Under the conditions studied, Kodak(r film is not influenced by disruption of fixation as regards BPFD and image contrast, enabling early access to the results of radiographs, whereas Agfa(r film requires at least 10 seconds of initial fixation, and Dentix(r film obtains better results when the process of fixation is not interrupted.

Periodontal disease is a kind of typical dental diseases, which affects many adults. The presence of alveolar bone resorption, which can be observed from dental panoramic radiographs, is one of the most important signs of the progression of periodontal disease. Automatically evaluating alveolar-bone resorption is of important clinic meaning in dental radiology. The purpose of this study was to propose a novel system for automated alveolar-bone-resorption evaluation from digital dental panoramic radiographs for the first time. The proposed system enables visualization and quantitative evaluation of alveolar bone resorption degree surrounding the teeth. It has the following procedures: (1) pre-processing for a test image; (2) detection of tooth root apices with Gabor filter and curve fitting for the root apex line; (3) detection of features related with alveolar bone by using image phase congruency map and template matching and curving fitting for the alveolar line; (4) detection of occlusion line with selected Gabor filter; (5) finally, evaluation of the quantitative alveolar-bone-resorption degree in the area surrounding teeth by simply computing the average ratio of the height of the alveolar bone and the height of the teeth. The proposed scheme was applied to 30 patient cases of digital panoramic radiographs, with alveolar bone resorption of different stages. Our initial trial on these test cases indicates that the quantitative evaluation results are correlated with the alveolar-boneresorption degree, although the performance still needs further improvement. Therefore it has potential clinical practicability.

To compare the prevalence of pulp calcification with that of carotid calcification using digital panoramic dental radiographs. Digital panoramic radiographs of patients at a dental oncology clinic were included if (1) the carotid artery bifurcation region was visible bilaterally and (2) the patient had non-restored or minimally restored molars and/or canines. An endodontist evaluated the images for pulpal calcifications in the selected teeth. An oral and maxillofacial radiologist independently evaluated the same images for calcifications in the carotid bifurcation region. Odds-ratio and Pearson {chi}{sup 2} were used for data analysis. Presence of pulpal calcification was also evaluated as a screening test for the presence of carotid calcification. A total of 247 panoramic radiographs were evaluated. 32% (n=80) had pulpal calcifications and 25% (n=61) had carotid calcifications with 12% (n=29) having both carotid and pulp calcifications. A significantly higher prevalence of both pulp and carotid calcification was found in subjects older than age 60 years compared to younger age groups. Accuracy of pulpal calcification in screening for carotid calcification was 66.4%. Both pulp and carotid calcifications were more prevalent in older individuals. The presence of pulp calcification was not a strong predictor for the presence of carotid calcification. (orig.)

Full Text Available Objectives: This study aimed to compare the diagnostic accuracy of inverted and unprocessed digitized periapical radiographs for detection of peri-implant defects.Materials and Methods: A total of 30 osteotomy sites were prepared in three groups of control, study group 1 with 0.425 mm defects and study group 2 with 0.725 mm defects using the SIC and Astra Tech drill systems with 4.25mm and 4.85mm diameters. Small and large defects were randomly created in the coronal 8mm of 20 implant sites; implants (3.4mm diameter, 14.5mm length were then placed. Thirty periapical (PA radiographs were obtained using Digora imaging system (Soredex Corporation, Helsinki, Finland, size 2 photostimulable storage phosphor (PSP plate sensors (40.0mm×30.0mm and Scanora software. Unprocessed images were inverted using Scanora software by applying image inversion and a total of 60 images were obtained and randomly evaluated by four oral and maxillofacial radiologists. Data were analyzed using the t-test.Results: Significant differences were observed in absolute and complete sensitivity and specificity of the two imaging modalities for detection of small and large defects (P<0.05. Unprocessed digitalimages had a higher mean in terms of absolute sensitivity for detection of small defects, complete sensitivity for detection of large peri-implant defects and definite rule out of defects compared with inverted images.Conclusion: Unprocessed digitalimages have a higher diagnostic value for detection of small and large peri-implant defects and also for definite rule out of defects compared with inverted images.

Scatter radiation is a source of noise and results in decreased signal-to-noise ratio and thus decreased image quality in digital radiography. We determined subjectively whether a digitally processed image made without a grid would be of similar quality to an image made with a grid but without image processing. Additionally the effects of exposure dose and of a using a grid with digital radiography on overall image quality were studied. Thoracic and abdominal radiographs of five dogs of various sizes were made. Four acquisition techniques were included (1) with a grid, standard exposure dose, digitalimage processing; (2) without a grid, standard exposure dose, digitalimage processing; (3) without a grid, half the exposure dose, digitalimage processing; and (4) with a grid, standard exposure dose, no digitalimage processing (to mimic a film-screen radiograph). Full-size radiographs as well as magnified images of specific anatomic regions were generated. Nine reviewers rated the overall image quality subjectively using a five-point scale. All digitally processed radiographs had higher overall scores than nondigitally processed radiographs regardless of patient size, exposure dose, or use of a grid. The images made at half the exposure dose had a slightly lower quality than those made at full dose, but this was only statistically significant in magnified images. Using a grid with digitalimage processing led to a slight but statistically significant increase in overall quality when compared with digitally processed images made without a grid but whether this increase in quality is clinically significant is unknown.

Personal identification is a vital arena of forensic investigation, facilitating the search for missing persons. This process of identification is eased by the determination of age, sex, and ethnicity. In situations where there are fragmented and mutilated skeletal remains, sex determination is relatively difficult, and it becomes important to establish the accuracy of individual bones. This study aims to evaluate sexual dimorphism in foramen magnum (FM) dimensions in the South Indian population using digital submentovertex (SMV) radiograph. 150 individuals (75 males and 75 females) were subjected to digital SMV radiography. FM in the resultant image was assessed for longitudinal and transverse diameters, circumference, and area. Also, one particular shape was assigned to each image based on the classification of Chethan et al. of FM shapes. Three qualified oral radiologists performed all the measurements twice within an interval of 10 days. The values obtained for all four parameters were statistically significant and higher in males than in females. The most common morphology of FM was an egg shape while hexagonal was the least common morphology. Circumference was the best indicator of sex followed by area, transverse diameter, and longitudinal diameter. Having achieved a high accuracy of 67.3% with digital SMV radiograph makes it a reliable and reproducible alternative to dry skulls for sex determination.

Full Text Available OBJECTIVE: The aim of this study was to compare the radiopacities of four different root canal sealers and gutta-percha. MATERIALS AND METHOD: AH Plus, iRootSP, MTA Fillapex and Sealapex as root canal sealers and gutta-percha cones were tested. Standardized discs of the root canal sealers and the gutta-percha were prepared. Digitalradiographs of the discs and an aluminum penetrometer were obtained by using a phosphor plate. The radiographic density of the sealers and the gutta-percha were measured by using the digitalradiographic system’s own measurement tool, and equivalent aluminum thicknesses were determined by using an image editing software. Differences among radiopacities of the root canal sealers and the gutta-percha were analyzed using One-way ANOVA and Tukey post-hoc tests. RESULTS: Aluminum thickness equivalents of the radiopacity values of the samples, in descending order, were: AH Plus, Sealapex, iRootSP, MTA Fillapex and gutta-percha. No significant difference was found between the radiopacity values of AH Plus and Sealapex (p>0.05. There were statistically significant differences between these two groups (AH Plus and Sealapex and all other experimental groups (p<0.05. CONCLUSION: AH Plus and Sealapex exhibited the highest radiopacity values among tested groups. In addition, all tested materials fulfilled the minimum standard value requirements suggested by International Standardization Organization and American National Standards Institute.

For some authors trabecular bone is highly visible in intraoral radiographs. For other authors, the observed intrabony trabecular pattern is a representation of only the endosteal surface of cortical bone, not of intermedullary striae. The purpose of this preliminary study was to investigate the true anatomical structures that are visible in routine dental radiographs and classically denoted trabecular bone. This is a major point for bone texture analysis on radiographs. Computed radiography (CR) images of dog mandible section in molar region were compared with simulations calculated from high-resolution micro-CT volumes. Calculated simulations were obtained using the Mojette Transform. By digitally editing the CT volume, the simulations were separated into trabecular and cortical components into a region of interest. Different images were compared and correlated, some bone micro-architecture parameters calculated. A high correlation was found between computed radiographs and calculated simulations from micro-CT. The Mojette transform was successful to obtain high quality images. Cortical bone did not contribute to change in a major way simulated images. These first results imply that intrabony trabecular pattern observed on radiographs can not only be a representation of the cortical bone endosteal surface and that trabecular bone is highly visible in intraoral radiographs.

Different digital medical images have been printed on paper with a continuous ink jet printer, and the quality has been evaluated. The emphasis has been on digital chest radiographs from a computed radiography system. The ink jet printing technique is described as well as the handling of the image data from image source to printer. Different versions of paper prints and viewing conditions were compared to find the optimum alternative. The evaluation has been performed to maximize the quality of the paper images to make them conform with the corresponding film prints and monitor images as much as possible. The continuous ink jet technique offers high-quality prints on paper at a considerably lower cost per copy compared with the cost of a film print. With a future switch-over from diagnosing of digitalimages on film to diagnosing them on monitors, hard copies for demonstration purposes will occasionally be needed. This need can be filled by ink jet-printed paper copies.

This study aimed to investigate the effect of changing the kilovoltage peak (kVp) on the radiographic assessment of dental caries. Seventy-five extracted posterior teeth with proximal caries or apparently sound proximal surfaces were radiographed with conventional E-speed films and a photostimulable phosphor system using 60 kVp and 70 kVp for the caries assessment. The images were evaluated by three oral radiologists and compared with the results of the stereomicroscope analysis. No statistically significant difference was found between 60 kVp and 70 kVp for the caries detection, determination of caries extension into dentin, and caries severity in either the conventional or the digitalimages. Good to very good inter-observer and intra-observer agreements were found for both kilovoltage values on the conventional and digitalimages. Changing the kilovoltage between 60 kVp and 70 kVp had no obvious effect on the detection of proximal caries or determination of its extension or severity.

In this paper, we address the issue of computer-assisted indexing in one specific case, i.e., for the 17,000 digitizedimages of the spine acquired during the National Health and Nutrition Examination Survey (NHANES). The crucial step in this process is to accurately segment the cervical and lumbar spine in the radiographicimages. To that end, we have implemented a unique segmentation system that consists of a suite of spine-customized automatic and semi-automatic statistical shape segmentation algorithms. Using the aforementioned system, we have developed experiments to optimally generate a library of spine segmentations, which currently include 2000 cervical and 2000 lumbar spines. This work is expected to contribute toward the creation of a biomedical Content-Based Image Retrieval system that will allow retrieval of vertebral shapes by using query by image example or query by shape example.

The aim of this study is the optimization of radiographicimages for the pediatric patients in the age range between 0 and 1 years old, through Optical Density Ratio (ODR), considering that pediatric patients are overexposed to radiation in the repeated attempts to obtain radiographicimages considered of good quality. The optimization of radiographic techniques was carried out with the RAP-PEPP (Realistic Analytical Phantom coupled to homogeneous Phantom Equivalent to Pediatric Patient) phantom in two incubators and one cradle. The data show that the clinical routine radiographic techniques generate low-quality images at up to 18.8% when evaluated by the ODRs, and increases in doses up to 60% when compared to the optimized techniques doses. (author)

Background: Identification of sex is the first step in forensic science obtained from skeletal remains. Mandible, being a strong bone that is difficult to damage and disintegrate, is an important tool in sex determination. The present study is aimed to assess, compare, and evaluate the mandibular measurements as seen on digital panoramic radiographs to analyze their use in sexual dimorphism assessment. Materials and Methods: This retrospective study was conducted using digital panoramic images of 100 each in both genders. Mandibular measurements were carried out utilizing RadiAnt DICOM Viewer 2.2.9 (32 bit) software (Medixant Company, Poland) and subjected to statistical analysis. Results: Descriptive statistics for all the parameters on the right and left sides of mandible in both males and females were analyzed. Inferential statistics were performed using t-test to compare males and females with different variables. A statistical significance of P < 0.001 has been demonstrated for all the variables (except linear measurement of mandibular foramen). All variables showed increased measurements in males than in females. The accuracy of sex determination in mandibular ramus measurements is 79.5% on right side and 77% on left side, where as, in linear mandibular measurements it is 76% on right side and 79.5% on left side. Conclusion: Mandibular measurements on digitalradiograph are useful in sex determination, and this study can be compared with other similar studies. PMID:27994407

DigitalImaging targets everyyone with an interest in digitalimaging, be they professional or private, who uses even quite modest equipment such as a PC, digital camera and scanner, a graphics editor such as Paint, and an inkjet printer. Uniquely, it is intended to fill the gap between highly technical texts for academics (with access to expensive equipment) and superficial introductions for amateurs. The four-part treatment spans theory, technology, programs and practice. Theory covers integer arithmetic, additive and subtractive color, greyscales, computational geometry, and a new presentation of discrete Fourier analysis; Technology considers bitmap file structures, scanners, digital cameras, graphic editors, and inkjet printers; Programs develops several processing tools for use in conjunction with a standard Paint graphics editor and supplementary processing tools; Practice discusses 1-bit, greyscale, 4-bit, 8-bit, and 24-bit images for the practice section. Relevant QBASIC code is supplied an accompa...

This paper deals with the noise analysis of radiographicimages obtained in the usual fluorescent screen-film system. The theory of nonstationary Poisson processes is applied to the analysis of the radiographicimages containing the object information. The ensemble averages, the autocorrelation functions, and the Wiener spectrum densities of the light-energy distribution at the fluorescent screen and of the film optical-density distribution are obtained. The detection characteristics of the system are evaluated theoretically. Numerical examples one-dimensional image are shown and the results are compared with those obtained under the assumption that the object image is related to the background noise by the additive process.

This paper deals with the noise analysis of radiographicimages obtained in the usual fluorescent screen-film system. The theory of nonstationary Poisson processes is applied to the analysis of the radiographicimages containing the object information. The ensemble averages, the autocorrelation functions, and the Wiener spectrum densities of the light-energy distribution at the fluorescent screen and of the film optical-density distribution are obtained. The detection characteristics of the system are evaluated theoretically. Numerical examples of the one-dimensional image are shown and the results are compared with those obtained under the assumption that the object image is related to the background noise by the additive process.

In radiotherapy treatment portal images and digitally reconstructed radiographs (DRRs) are the most frequently used image-guidance systems to monitor patient set-up during clinical routine. DRR is therefore a critical element in the process of virtual simulation and patient position verification in radiotherapy. The aim of this work was to assess the geometric reliability of the DRR generated by XiO, Pinnacle, Odyssey and Ocentra-Masterplan Treatment Planning Systems (TPS). Instead of the Computed Tomography (CT) images of a quality assurance phantom two synthetic phantoms were created and used to asses the linearity and the ray tracing reliability of the DRR generators. The obtained results demonstrate that the linearity and the reliability of DRR generators was less than 1 pixel for all TPSs.

This study compared the gray value differences to dentin of titanium and FRC root posts in anterior and posterior teeth radiographed with digital intraoral systems and conventional x-ray film. Radiographicimages (n=5) of titanium or fiber-reinforced composite (FRC) root posts placed in extracted teeth were taken with six digital intraoral radiographic devices and conventional x-ray film (control group). Gray value differences were evaluated between the root posts and root dentin. Statistical analyses of the results were performed with three-way and one-way ANOVA with Bonferroni-Dunn's multiple comparisons post-hoc analyses (α=0.05). Significantly higher gray value differences of titanium and FRC posts were found in anterior teeth but not in molars for XIOS, Sidexis and Visualix digital intraoral systems, but not for RVG, DenOptix and VistaScan (FRC posts). Except for DenOptix with incisors and molars and VistaScan with molars, conventional x-ray films showed significantly lower gray value differences of titanium posts in incisors and molars compared to the corresponding digitalradiographs.

Full Text Available ABSTRACT Objective: The aim of this study was to compare the equivalent and effective doses of different digitalradiographic methods (panoramic, lateral cephalometric and periapical with cone-beam computed tomography (CBCT. Methods: Precalibrated thermoluminescent dosimeters were placed at 24 locations in an anthropomorphic phantom (Alderson Rando Phantom, Alderson Research Laboratories, New York, NY, USA, representing a medium sized adult. The following devices were tested: Heliodent Plus (Sirona Dental Systems, Bernsheim, Germany, Orthophos XG 5 (Sirona Dental Systems, Bernsheim, Germany and i-CAT (Imaging Sciences International, Hatfield, PA, USA. The equivalent doses and effective doses were calculated considering the recommendations of the International Commission of Radiological Protection (ICRP issued in 1990 and 2007. Results: Although the effective dose of the radiographic set corresponded to 17.5% (ICRP 1990 and 47.2% (ICRP 2007 of the CBCT dose, the equivalent doses of skin, bone surface and muscle obtained by the radiographic set were higher when compared to CBCT. However, in some areas, the radiation produced by the orthodontic set was higher due to the complete periapical examination. Conclusion: Considering the optimization principle of radiation protection, i-CAT tomography should be used only in specific and justified circumstances. Additionally, following the ALARA principle, single periapical radiographies covering restricted areas are more suitable than the complete periapical examination.

ABSTRACT Objective: The aim of this study was to compare the equivalent and effective doses of different digitalradiographic methods (panoramic, lateral cephalometric and periapical) with cone-beam computed tomography (CBCT). Methods: Precalibrated thermoluminescent dosimeters were placed at 24 locations in an anthropomorphic phantom (Alderson Rando Phantom, Alderson Research Laboratories, New York, NY, USA), representing a medium sized adult. The following devices were tested: Heliodent Plus (Sirona Dental Systems, Bernsheim, Germany), Orthophos XG 5 (Sirona Dental Systems, Bernsheim, Germany) and i-CAT (Imaging Sciences International, Hatfield, PA, USA). The equivalent doses and effective doses were calculated considering the recommendations of the International Commission of Radiological Protection (ICRP) issued in 1990 and 2007. Results: Although the effective dose of the radiographic set corresponded to 17.5% (ICRP 1990) and 47.2% (ICRP 2007) of the CBCT dose, the equivalent doses of skin, bone surface and muscle obtained by the radiographic set were higher when compared to CBCT. However, in some areas, the radiation produced by the orthodontic set was higher due to the complete periapical examination. Conclusion: Considering the optimization principle of radiation protection, i-CAT tomography should be used only in specific and justified circumstances. Additionally, following the ALARA principle, single periapical radiographies covering restricted areas are more suitable than the complete periapical examination. PMID:27653266

Automated detection of welding defects in radiographicimages becomes non-trivial when uneven illumination, contrast and noise are present. In this paper, a new surface thresholding method is introduced to detect defects in radiographicimages of welding joints. In the first stage, several image processing techniques namely fuzzy c means clustering, region filling, mean filtering, edge detection, Otsu's thresholding and morphological operations method are utilised to locate the area in which defects might exist. This is followed by the implementation of inverse surface thresholding with partial differential equation to locate isolated areas that represent the defects in the second stage. The proposed method obtained a promising result with high precision.

Digital radiography devices, rapidly replacing analog screen-film detectors, are now common in diagnostic radiological imaging, where implementation has been accelerated by the commodity status of electronic imaging and display systems. The shift from narrow latitude, fixed-speed screen-film detectors to wide latitude, variable-speed digital detectors has created a flexible imaging system that can easily result in overexposures to the patient without the knowledge of the operator, thus potentially increasing the radiation burden of the patient population from radiographic examinations. In addition, image processing can be inappropriately applied causing inconsistent or artifactual appearance of anatomy, which can lead to misdiagnosis. On the other hand, many advantages can be obtained from the variable-speed digital detector, such as an ability to lower dose in many examinations, image post-processing for disease-specific conditions, display flexibility to change the appearance of the image and aid the physician in making a differential diagnosis, and easy access to digitalimages. An understanding of digital radiography is necessary to minimize the possibility of overexposures and inconsistent results, and to achieve the principle of as low as reasonably achievable (ALARA) for the safe and effective care of all patients. Thus many issues must be considered for optimal implementation of digital radiography, as reviewed in this article.

Full Text Available This in vitro study evaluated and compared the efficacy of conventional (Kodak F-speed (Insight, Kodak and a digital (DRS Gnatus System, Gnatus radiographicimaging for diagnosis of simulated external root resorption cavities. Human mandibles containing teeth were covered with bovine muscle slices in order to simulate the soft tissues. Nine teeth out of each group of teeth were investigated. Initially, three periapical radiographs of each tooth were taken using a tube shift technique with mesial and distal angulations in both methods. All teeth were subsequently extracted and had 0.7 and 1.0-mm deep cavities prepared on their buccal, mesial and distal surfaces at the cervical, middle and apical thirds. Steel cylinder burs (DORMER® - HSS with 0.7 and 1.0-mm diameter were used. Each tooth was replaced on its socket and new radiographs were taken. Three examiners, an endodontist (1, a radiologist (2 and a general dentist (3, evaluated the images. Results were compared by z-test and showed a higher number of cavities detected by the digital method compared to the conventional, regardless of the deepness of the cavity. In decreasing order, examiners 2, 3 and 1 exhibited different potentials of detection of cavities with the conventional method. Examiners 1 and 3 exhibited superior potential than examiner 2 for detection of cavities of different sizes with the digital method.O presente estudo visou avaliar e comparar, in vitro, a eficácia dos métodos radiográficos convencional (filmes de grupos de sensibilidade E/F Kodak Insight e digital (Sistema Gnatus DRS, no diagnóstico de cavidades simulando reabsorções radiculares externas, em dentes contidos em mandíbulas humanas secas com músculo bovino simulando o tecido mole. As variáveis consideradas foram: tamanhos das cavidades e examinadores envolvidos. Foram utilizadas nove unidades de cada grupo dentário, incisivos (central e lateral, caninos, pré-molares e molares, sem lesões periapicais

Full Text Available Objectives: The purpose of this study was to develop and test a new tool for radiographic densitometry by combining periapical films and aluminum step wedge.Materials and Methods: We reviewed 50 Kodak E-speed intraoral films. An aluminum step wedge consisting of 16 steps was constructed. Each step was 1mmx3mx10mm. The step wedge was exposed to varying exposure times, ranging from 0.05 second to 0.5 second, increasing in 0.05 second increments. Films were digitalized after processing and the MATLAB software algorithm was ran subsequently. Density of the films was measured again using a digital densitometer. In order to compare the two imaging techniques, three steps were selected. Output data from the MATLAB algorithm were compared with data obtained from the digital densitometer.Results: The new method could detect significant differences between subsequent exposure times in step 7, while the densitometer did that in steps 7 and 12. The new method’s sensitivity in determining density changes was 5.26%, 84.1% and 93.02% in steps 2, 7, and 12 respectively.Conclusions: Our new method has an acceptable sensitivity for determining density changes of at least 7 mmEq/Al.Keywords: Densitometry; Image Processing, Computer-Assisted; Aluminum; Phantoms, Imaging

Three kinds of artifacts unique to digitalimages are illustrated, namely aliasing caused by undersampling, interference phenomena caused by improper display of images, and harmonic overtones caused by quantization of amplitudes. Special attention is given to undersampling when the sample size and interval are the same. It is noted that this situation is important because it is typical of solid-state cameras. Quantization of image data of necessity introduces energy at harmonic overtones of the image spectrum. This energy is aliased if the frequency of the overtones is greater than 0.5 cycle/pixel. It cannot be selectively removed from the image through filtering, and the best way to suppress it is to maximize the amplification of the sensor before digital encoding.

We developed the standard digitalimages (SDIs) to be used in the classification and recognition of pneumoconiosis. From July 3, 2006 through August 31, 2007, 531 retired male workers exposed to inorganic dust were examined by digital (DR) and analog radiography (AR) on the same day, after being approved by our institutional review board and obtaining informed consent from all participants. All images were twice classified according to the International Labour Office (ILO) 2000 guidelines with reference to ILO standard analog radiographs (SARs) by four chest radiologists. After consensus reading on 349 digitalimages matched with the first selected analog images, 120 digitalimages were selected as the SDIs that considered the distribution of pneumoconiosis findings. Images with profusion category 0/1, 1, 2, and 3 were 12, 50, 40, and 15, respectively, and a large opacity were in 43 images (A = 20, B = 22, C = 1). Among pleural abnormality, costophrenic angle obliteration, pleural plaque and thickening were in 11 (9.2%), 31 (25.8%), and 9 (7.5%) images, respectively. Twenty-one of 29 symbols were present except cp, ef, ho, id, me, pa, ra, and rp. A set of 120 SDIs had more various pneumoconiosis findings than ILO SARs that were developed from adequate methods. It can be used as digital reference images for the recognition and classification of pneumoconiosis.

This collective work identifies the latest developments in the field of the automatic processing and analysis of digital color images.For researchers and students, it represents a critical state of the art on the scientific issues raised by the various steps constituting the chain of color image processing.It covers a wide range of topics related to computational color imaging, including color filtering and segmentation, color texture characterization, color invariant for object recognition, color and motion analysis, as well as color image and video indexing and retrieval. <

DigitalImaging is the essential guide to understanding digitization and managing a digitizing project. Koelling covers everything from deciding if digitizing is for you to planning and management, choosing equipment, and managing databases. Not only does she guide you in mastering the technical details, she also helps you find the fun in working with images.

Shortly after Röntgen discovered x-rays urology became one of the main test fields for the application of this new technology. Initial scepticism among physicians, who were inclined to cling to traditional manual methods of diagnosing, was replaced by enthusiasm for radiographic technologies and the new method soon became the standard in, for example the diagnosis of concrements. Patients favoring radiographic procedures over the use of probes and a convincing documentation of stones in radiograms were factors that impacted the relatively rapid integration of radiology into urology. The radiographic representation of soft tissues and body cavities was more difficult and the development of contrast agents in particular posed a serious problem. Several patients died during this research. A new diagnostic dimension was revealed when radiography and cystography were combined to form the method of retrograde pyelography. However, the problem of how urologists could learn how to read the new images remained. In order to allow trainee physicians to practice interpreting radiograms atlases were produced which offered explanatory texts and drawings for radiographicimages of the kidneys, the bladder etc. Thus, urologists developed a self-contained semiotics which facilitated the appropriation of a unique urological radiographical gaze.

Information technology is vital to operations, marketing, accounting, finance and administration. One of the most exciting and quickly evolving technologies in the modern dental office is digital applications. The dentist is often the business manager, information technology officer and strategic planning chief for his small business. The information systems triangle applies directly to this critical manager supported by properly trained ancillary staff and good equipment. With emerging technology driving all medical disciplines and the rapid pace at which it emerges, it is vital for the contemporary practitioner to keep abreast of the newest information technology developments. This article compares the strategic and operational advantages of digital applications, specifically imaging. The focus of this paper will be on digital radiography (DR), 3D computerized tomography, digital photography and digitally-driven CAD/CAM to what are now considered obsolescing modalities and contemplates what may arrive in the future. It is the purpose of this essay to succinctly evaluate the decisions involved in the role, application and implications of employing this tool in the dental environment

The growing importance of three-dimensional radiotherapy treatment has been associated with the active presence of advanced computational workflows that can simulate conventional x-ray films from computed tomography (CT) volumetric data to create digitally reconstructed radiographs (DRR). These simulated x-ray images are used to continuously verify the patient alignment in image-guided therapies with 2D-3D image registration. The present DRR rendering pipelines are quite limited to handle huge imaging stacks generated by recent state-of-the-art CT imaging modalities. We present a high performance x-ray rendering pipeline that is capable of generating high quality DRRs from large scale CT volumes. The pipeline is designed to harness the immense computing power of all the heterogeneous computing platforms that are connected to the system relying on OpenCL. Load-balancing optimization is also addressed to equalize the rendering load across the entire system. The performance benchmarks demonstrate the capability of our pipeline to generate high quality DRRs from relatively large CT volumes at interactive frame rates using cost-effective multi-GPU workstations. A 5122 DRR frame can be rendered from 1024 × 2048 × 2048 CT volumes at 85 frames per second.

This report describes the radiation dosage reduction possible in the general dental practice with two CCD (charge-coupled device)-based intraoral radiographic systems: the RVG-S (Trophy Radiologie, Vincennes, France) and the Sens-A-Ray (Regam Medical Systems, Sundsvall, Sweden). Radiation dosages (air-kerma; Gy) necessary for obtaining clinically acceptable images were measured at the cone tip using an ionization chamber type 660-1 (Nuclear Associates, Victoreen, Inc., Carle Place, New York, USA). When the RVG-S was used with an Oramatic 70 (Trophy Radiologie) X-ray generator, dosages at the cone tip ranged from 322 to 612 microGy. These corresponded to 40-60% of the dosages necessary when using Ektaspeed dental X-ray film (Eastman Kodak, Rochester, New York, USA) with a Heliodent 70 (Siemens, Erlangen, Germany) X-ray generator. At 60 kVp, the Sens-A-Ray reduced the dosage in the order of 30% compared with Ektaspeed dental X-ray film. Reduction in radiation dosage is one of the benefits of digital intraoral radiographic systems in general dental clinics. The RVG-S provides greater dose savings than does the Sens-A-Ray.

Introduction: Radiographers evaluate anatomical structures to judge clinical acceptability of a radiograph. Whether a radiograph is deemed acceptable for diagnosis or not depends on the individual decision of the radiographer. Individual decisions cause variation in the accepted image quality. To minimise these variations definitions of acceptability, such as in RadLex, were developed. On which criteria radiographers attribute a RadLex categories to radiographs is unknown. Insight into these criteria helps to further optimise definitions and reduce variability in acceptance between radiographers. Therefore, this work aims the evaluation of the correlation between the RadLex classification and the evaluation of anatomical structures, using a Visual Grading Analysis (VGA) Methods: Four radiographers evaluated the visibility of five anatomical structures of 25 lateral cervical spine radiographs on a secondary class display with a VGA. They judged clinical acceptability of each radiograph using RadLex. Relations between VGAS and RadLex category were analysed with Kendall's Tau correlation and Nagelkerke pseudo-R². Results: The overall VGA score (VGAS) and the RadLex score correlate (rτ= 0.62, pConclusion: RadLex scores and VGAS correlate positively, strongly and significantly. The predictive value of bony structures may support the use of these in the judgement of clinical acceptability. Considerable inter-observer variations in the VGAS within a certain RadLex category, suggest that observers use of observer specific cut-off values.

Background Diagnosis and accuracy in determining the exact location, extent and configuration of bony defects of the jaw are of utmost importance to determine prognosis, treatment planning and long-term preservation of teeth. If relatively accurate diagnosis can be established by radiography, proper treatment planning prior to treatment procedures will be possible. Objectives The aim of the present study was to assess the correlation between indirect digitalradiographic measurements and clinical measurements in determining the topography of interproximal bony defects. Patients and Methods Twenty interproximal bony defects, preferably in the mandibular and maxillary 5↔5 area were selected and radiographed using the parallel periapical technique. The radiographs were corrected and digitized on a computer using “Linear Measurement” software; then the three parameters of the base of defect (BD), alveolar crest (AC) and cementoenamel junction (CEJ) were determined using a software. Subsequent to radiographic measurements, clinical measurements were carried out meticulously during flap procedures. Then linear measurements were carried out using a periodontal probe to determine the defect depth and its mesiodistal width. Then the amount of correlation between these two measurements was assessed by Pearson's correlation coefficient. Results The correlation between clinical and radiographic measurements in defect depth determination, in the evaluation of defect angle and in determination of defect width were 88%, 98% and 90%, respectively. Conclusions Indirect digitalradiographic technique can be used to diagnose intra-osseous defects, providing a better opportunity to treat bony defects. PMID:23329969

Objectives: The objective of this study was to evaluate the prevalence of dental developmental anomalies in digital panoramic radiographs of the patients referred to the Zahedan medical imaging center and to evaluate the frequency of anomalies regarding the disorders in shape, position and number in the Southeast of Iran. Materials and Methods: A total of 1172 panoramic radiographs from 581 males and 586 females aged over 16 years were obtained from the files of the Zahedan medical imaging center between the years of 2014 and 2015. The selected radiographs were evaluated in terms of the anomalies such as dilacerations, taurodontism, supernumerary teeth, congenitally missing teeth, fusion, gemination, tooth impaction, tooth transposition, dens invagination, and peg lateral. Then, the anomalies were compared to each other regarding the frequency of the anomaly type (morphological, positional and numerical). Data were evaluated using descriptive statistics such as frequency and percent, and statistical tests such as X2 at 0.05 significant level using the Statistical Package for the Social Sciences version 16.5. Results: The prevalence of dental anomaly was 213 (18.17%), which was higher in females (9.90) than male, (8.28), however, this difference was not statistically significant (P > 0.05). The prevalence of dilacerated teeth was 62 (5.29%), taurodontism 63 (5.38%), supernumerary teeth 6 (0.51%), congenitally missing teeth 13 (1.11%), fusion 1 (0.09%), gemination 1 (0.09%), impaction 40 (3.41%), transposition 2 (0.18%), dens invagination 16 (1.37) and peg lateral was 9 (0.77%). The prevalence of morphological anomaly was 152 (71.36%), malposition 42 (19.72%) and numerous anomaly was 19 (8.92%). Conclusions: Dental anomalies are relatively common; although their occurrence is not symptomatic, they can lead to several clinical problems in patients. Detailed clinical and radiographic assessment and counseling during patient visits is a critical factor in assessing the

Purpose In the present study, we coined the term 'alveolar dome' and aimed to demonstrate the prevalence of alveolar domes through digital periapical radiographs. Materials and Methods This study examined 800 digital periapical radiographs in regard to the presence of alveolar domes. The periapical radiographs were acquired by a digital system using a photostimulable phosphor (PSP) plate. The χ2 test, with a significance level of 5%, was used to compare the prevalence of alveolar domes in the maxillary posterior teeth and, considering the same teeth, to verify the difference in the prevalence of dome-shaped phenomena between the roots. Results The prevalence of alveolar domes present in the first pre-molars was statistically lower as compared to the other maxillary posterior teeth (pauxiliary information necessary to identify alveolar domes, thus improving diagnosis, planning, and treatment. PMID:27672614

A new approach for contrast enhancement of chest radiographimage data is presented. Existing methods for image enhancement focus mainly on the properties of the image to be processed while excluding any consideration of the observer characteristics. In several applications, particularly in the medical imaging area, effective contrast enhancement for diagnostic purposes can be achieved by including certain basic human visual properties. In this paper we shall present a novel (recursive) algorithm that tailors the required amount of contrast enhancement based on a combination of the optimal phase representation and the theory of projection onto a convex set. Constraints of maximum bandwidth of the image data, appropriate knowledge of the amplitude value of the image data, heuristic limitations and level crossing measurements serve to impose additional information. So that, the enhanced image data may better converge to the good quality image.

Exploring theories and applications developed during the last 30 years, Digital Geometry in Image Processing presents a mathematical treatment of the properties of digital metric spaces and their relevance in analyzing shapes in two and three dimensions. Unlike similar books, this one connects the two areas of image processing and digital geometry, highlighting important results of digital geometry that are currently used in image analysis and processing. The book discusses different digital geometries in multi-dimensional integral coordinate spaces. It also describes interesting properties of

Operative treatment of an intra-articular distal radius fracture is one of the most common procedures in orthopedic and hand surgery. The intra- and interobserver agreement of common radiographical measurements of these fractures using cone beam computed tomography (CBCT) and plain radiographs were evaluated. Thirty-seven patients undergoing open reduction and volar fixation for a distal radius fracture were studied. Two radiologists analyzed the preoperative radiographs and CBCT images. Agreement of the measurements was subjected to intra-class correlation coefficient and the Bland-Altman analyses. Plain radiographs provided a slightly poorer level of agreement. For fracture diastasis, excellent intraobserver agreement was achieved for radiographs and good or excellent agreement for CBCT, compared to poor interobserver agreement (ICC 0.334) for radiographs and good interobserver agreement (ICC 0.621) for CBCT images. The Bland-Altman analyses indicated a small mean difference between the measurements but rather large variation using both imaging methods, especially in angular measurements. For most of the measurements, radiographs do well, and may be used in clinical practice. Two different measurements by the same reader or by two different readers can lead to different decisions, and therefore a standardization of the measurements is imperative. More detailed analysis of articular surface needs cross-sectional imaging modalities. (orig.)

Bone age assessment is a procedure frequently performed in pediatric patients to evaluate their growth disorder. A commonly used method is atlas matching by a visual comparison of a hand radiograph with a small reference set of old Greulich-Pyle atlas. We have developed a new digital hand atlas with a large set of clinically normal hand images of diverse ethnic groups. In this paper, we will present our system design and implementation of the digital atlas database to support the computer-aided atlas matching for bone age assessment. The system consists of a hand atlas image database, a computer-aided diagnostic (CAD) software module for image processing and atlas matching, and a Web user interface. Users can use a Web browser to push DICOM images, directly or indirectly from PACS, to the CAD server for a bone age assessment. Quantitative features on the examined image, which reflect the skeletal maturity, are then extracted and compared with patterns from the atlas image database to assess the bone age. The digital atlas method built on a large image database and current Internet technology provides an alternative to supplement or replace the traditional one for a quantitative, accurate and cost-effective assessment of bone age.

Computed Radiography (CR) has become a major digitalimaging modality in a modern radiological department. CR system changes workflow from the conventional way of using film/screen by employing photostimulable phosphor plate technology. This results in the changing perspectives of technical, artefacts and quality control issues in radiology departments. Guidelines for better image quality in digital medical enterprise include professional guidelines for users and the quality control programme...

Full Text Available Background: Diagnosis and accuracy in determining the exact location, extent and configurationof bony defects of the jaw are of utmost importance to determine prognosis,treatment planning and long-term preservation of teeth. If relatively accurate diagnosiscan be established by radiography, proper treatment planning prior to treatment procedureswill be possible.Objectives: The aim of the present study was to assess the correlation between indirectdigital radiographic measurements and clinical measurements in determining the topographyof interproximal bony defects.Patients and Methods: Twenty interproximal bony defects, preferably in the mandibularand maxillary 5↔5 area were selected and radiographed using the parallel periapical technique.The radiographs were corrected and digitized on a computer using “Linear Measurement”software; then the three parameters of the base of defect (BD, alveolar crest(AC and cementoenamel junction (CEJ were determined using a software. Subsequentto radiographic measurements, clinical measurements were carried out meticulouslyduring flap procedures. Then linear measurements were carried out using a periodontalprobe to determine the defect depth and its mesiodistal width. Then the amount of correlationbetween these two measurements was assessed by Pearson's correlation coefficient.Results: The correlation between clinical and radiographic measurements in defect depthdetermination, in the evaluation of defect angle and in determination of defect widthwere 88%, 98% and 90%, respectively.Conclusions: Indirect digitalradiographic technique can be used to diagnose intra-osseousdefects, providing a better opportunity to treat bony defects.

The aircraft structures are made of aluminium alloys because of its various advantages, including ease of manufacture, high tolerance and ease of maintenance. Corrosions and cracks are often found in high-strength aluminium alloys. The industrial radiographic testing method and digital radiography are two most important tools for detecting different kinds of defects in aluminium structures. However, because of greater sensitivity and dynamic range of phosphor plates in computed radiography than in film, digital radiography can produce clear and high-contrast images, but digital radiography images appear foggy. In this study, a dehazing algorithm is implemented for the digital radiography images of airplane parts to remove fog. The used dehazing algorithm is based on the dark channel prior and it is based on the statistics of outdoor haze-free images. In most of the local regions of the radiography images, some pixels very often have very low intensity in at least one colour (RGB: red, green, blue) channel which are called dark pixels. In hazy radiography images, the intensity of these dark pixels in that channel is mainly contributed by scattering. Therefore, these dark pixels can directly provide an accurate estimation of the haze transmission and combining a haze imaging model and a soft matting interpolation method can be recovered a high-quality haze free in the radiography image and produce a good depth map and the defects. The results show that the fog-removed images have better contrast and the shapes of defects are very clear. In addition, some invisible cracks in the digitalimages can be seen in the defogged image.

In this article we study the digital homology groups of digitalimages which are based on the singular homology groups of topological spaces in algebraic topology. Specifically, we define a digitally standard $n$-simplex, a digitally singular $n$-simplex, and the digital homology groups of digitalimages with $k$-adjacency relations. We then construct a covariant functor from a category of digitalimages and digitally continuous functions to the one of abelian groups and group homomorphisms, and investigate some fundamental and interesting properties of digital homology groups of digitalimages, such as the digital version of the dimension axiom which is one of the Eilenberg-Steenrod axioms.

Digitally reconstructed radiographs (DRRs) play a significant role in modern clinical radiation therapy. They are used to verify patient alignments during image guided therapies with 2D-3D image registration. The generation of DRRs can be implemented intuitively in O(N3) relying on direct volume rendering (DVR) methods, such as ray marching. This complexity imposes certain limitations on the rendering performance if high quality DRR images are needed. Those DRRs can be alternatively generated in the k-space using the central slice theorem in O(N2logN). Several rendering pipelines have been designed to create the DRRs in the k-space, but they were either limited to specific vendor or entail particular software requirements. We present a high performance implementation of a k-space-based DRR generation pipeline that is executable on various heterogeneous computing architectures using OpenCL. Our implementation generates a DRR for a 5123 CT volume in 6, 2.7 and 0.68 milli-seconds on a commodity CPU, mid-range and high-end GPUs respectively.

The radiopacity of esthetic restorative materials has been established as an important requirement, improving the radiographic diagnosis. The aim of this study was to evaluate the radiopacity of six restorative materials using a direct digitalimage system, comparing them to the dental tissues (enamel-dentin), expressed as equivalent thickness of aluminum (millimeters of aluminum). Five specimens of each material were made. Three 2-mm thick longitudinal sections were cut from an intact extracted permanent molar tooth (including enamel and dentin). An aluminum step wedge with 9 steps was used. The samples of different materials were placed on a phosphor plate together with a tooth section, aluminum step wedge and metal code letter, and were exposed using a dental x-ray unit. Five measurements of radiographic density were obtained from each image of each item assessed (restorative material, enamel, dentin, each step of the aluminum step wedge) and the mean of these values was calculated. Radiopacity values were subsequently calculated as equivalents of aluminum thickness. Analysis of variance (ANOVA) indicated significant differences in radiopacity values among the materials (Pcomposite restorations it is important that the restorative material to be used has enough radiopacity, in order to be easily distinguished from the tooth structure in the radiographicimage. Knowledge on the radiopacity of different materials helps professionals to select the most suitable material, along with other properties such as biocompatibility, adhesion and esthetic.

This study was performed to observe the secondary images and to analyse the relationships between the primary and secondary images in panoramic radiograph. Using the Morita's Panex-EC panoramic x-ray machine and the human dry skull, the author analysed 17 radiographs which were selected from 65 radiographs of the dry skull that attached the radiopaque materials, and the attached regions of the radiopaque materials were the normal anatomical structures which were important and selected as a region for the evaluation of the secondary images effectively. The results were as follows; 1. The cervical vertebrae showed three images. The midline image was the most distorted and less clear, and bilateral images were slightly superimposed over the posterior border of the mandibular ramus. 2. In mandible, the secondary image of the posterior border of the ramus was superimposed on the opposite ramus region, and this image was elongated from the anterior border of the ramus to the lateral side of the posterior border of the ramus. The secondary image of the condyle was observed on the upper area of the coronoid process, the sigmoid notch and the condyle in opposite side. 3. In maxilla, the posterior region of the hard palate showed the secondary image on the lower part of the nasal cavity and the medial wall of the maxillary sinus. 4. The primary images of the occipital condyle and the mastoid process appeared on the same region, and only the secondary image of the occipital condyle was observed symmetrically on the opposite side with similar shape to the primary one. 5. In the cranial base, the anatomical structures of the midsagittal portions like a inferior border of the frontal sinus, sella turcica, inferior border of the sphenoid sinus and inferior border of the posterior part of the occipital bone showed the similar shape between the primary and secondary images symmetrically. 6. The petrous portion of the temporal bone showed the secondary image of the lateral side

Correct measurement of crown length is important for calculating the crown-implant ratio. The aim of this study was to compare the length of implant-supported crowns measured on digitized casts and intraoral radiographs. Crown lengths were studied in 50 patients with 86 implant-supported crowns in t

A resolution gauge was fabricated for measuring the spatial resolution of radiographicimaging systems. Silicon wafers, 100 mm , were patterned using standard contact lithography and the patterned features were etched using deep reactive ion etching (DRIE). The smallest features were 5 μm wide line pairs. The resulting etched trenches included aspect ratios of up to 10:1 and were 40.6±0.2 μm deep. The etch rate was 2.7 μm/min for the reported etch depth. A Gd 2O 3 nanopowder was dispersed into a slurry using Darvan C and water as the dispersant and solvent, respectively. A rapid infiltration method was used to fill the etched trenches with the slurry. Neutron and X-ray radiographs of the resolution gauge and the results demonstrate that the prototype gauge would be a suitable standard for measuring the spatial resolution of both X-ray and neutron radiography systems.

Full Text Available This in vivo study evaluated the dissociation quality of maxillary premolar roots combining variations of vertical and horizontal angulations by using X-ray holders (Rinn -XCP, and made a comparison between two types of intraoral radiography systems - conventional film (Kodak Insight, Rochester, USA and digital radiography (Kodak RVG 6100, Kodak, Rochester, USA. The study sample was comprised of 20 patients with a total of 20 maxillary premolars that were radiographed, using the paralleling angle technique (GP, with a 20º variation of the horizontal angle (GM and 25º variation of the horizontal angle combined with 15º vertical angle (GMV. Each image was independently analyzed by two experienced examiners. These examiners assigned a score to the diagnostic capability of root dissociation and the measurement of the distance between the apexes. Statistical data was derived using the Wilcoxon Signed Rank test, Friedman and T test. The means of the measured distances between buccal and lingual root apexes were greater for the GMV, which ranged from 2.3 mm to 3.3 mm. A statistically significant difference was found between GM and GMV when compared to GP with p < 0.01. An established best diagnostic dissociation roots image was found in the GMV. These results support the use of the anterior X-ray holders which offer a better combined deviation (GMV to dissociate maxillary premolar roots in both radiography systems.

In recent years, Moore's law has fostered the steady growth of the field of digitalimage processing, though the computational complexity remains a problem for most of the digitalimage processing applications. In parallel, the research domain of optical image processing has matured, potentially bypassing the problems digital approaches were suffering and bringing new applications. The advancement of technology calls for applications and knowledge at the intersection of both areas but there is a clear knowledge gap between the digital signal processing and the optical processing communities. T

The authors describe a new program for cephalometric analysis which uses a commonly available microprocessor (computer) and digitizing pad to register fifteen commonly identified cephalometric landmarks to produce a meaningful analysis which is printed out for permanent or hard-copy record. Conventional and digitizing errors of cephalometric measurement are reviewed, with a discussion of the advantages of computer-assisted programs. The authors describe a program that uses vectors and vector algebra and the capabilities of the Pascal computer language to determine angular measurements and distances. It is suggested that computer-assisted cephalometric programs will likely be widely used in the near future, providing the orthodontist with a superior method of cephalometric analysis with respect to accuracy and speed of completion.

To investigate image interpretation performance by diagnostic radiography students, diagnostic radiographers and reporting radiographers by computing eye gaze metrics using eye tracking technology. Three groups of participants were studied during their interpretation of 8 digitalradiographicimages including the axial and appendicular skeleton, and chest (prevalence of normal images was 12.5%). A total of 464 image interpretations were collected. Participants consisted of 21 radiography students, 19 qualified radiographers and 18 qualified reporting radiographers who were further qualified to report on the musculoskeletal (MSK) system. Eye tracking data was collected using the Tobii X60 eye tracker and subsequently eye gaze metrics were computed. Voice recordings, confidence levels and diagnoses provided a clear demonstration of the image interpretation and the cognitive processes undertaken by each participant. A questionnaire afforded the participants an opportunity to offer information on their experience in image interpretation and their opinion on the eye tracking technology. Reporting radiographers demonstrated a 15% greater accuracy rate (p≤0.001), were more confident (p≤0.001) and took a mean of 2.4s longer to clinically decide on all features compared to students. Reporting radiographers also had a 15% greater accuracy rate (p≤0.001), were more confident (p≤0.001) and took longer to clinically decide on an image diagnosis (p=0.02) than radiographers. Reporting radiographers had a greater mean fixation duration (p=0.01), mean fixation count (p=0.04) and mean visit count (p=0.04) within the areas of pathology compared to students. Eye tracking patterns, presented within heat maps, were a good reflection of group expertise and search strategies. Eye gaze metrics such as time to first fixate, fixation count, fixation duration and visit count within the areas of pathology were indicative of the radiographer's competency. The accuracy and confidence of

Today it is essential to use X-ray diagnosis in health, so it is essential that professionals have a strong background in all aspects of radiological images dependent. It is also necessary to understand the dependence between dose and image quality and thus introduce the concept of optimization in the performance of radiologic studies, from a simple test to a complex, establishing a dependency between patient dose and the aim of the study to be performed.

Trabecular bone is a highly complex anisotropic material that exhibits varying magnitudes of strength in compression and tension. Analysis of the trabecular architectural alteration that manifest as loss of trabecular plates and connection has been shown to yield better estimation of bone strength. In this work, an attempt has been made toward the development of an automated system for investigation of trabecular femur bone architecture using fractal analysis. Conventional radiographic femur bone images recorded using standard protocols are used in this study. The compressive and tensile regions in the images are delineated using preprocessing procedures. The delineated images are analyzed using Higuchi's fractal method to quantify pattern heterogeneity and anisotropy of trabecular bone structure. The results show that the extracted fractal features are distinct for compressive and tensile regions of normal and abnormal human femur bone. As the strength of the bone depends on architectural variation in addition to bone mass, this study seems to be clinically useful.

Full Text Available OBJECTIVE: The aim of the present study was to evaluate the radiopacity of Portland and MTA-based cements using the Digora TM digitalradiographic system. MATERIAL AND METHODS: The performed tests followed specification number 57 from the American National Standard Institute/American Dental Association (2000 for endodontic sealing materials. The materials were placed in 5 acrylic plates, especially designed for this experiment, along with a graduated aluminum stepwedge varying from 1 to 10 mm in thickness. The set was radiographed at a 30 cm focus-object distance and with 0.2 s exposure time. After the radiographs were taken, the optical laser readings of radiographs were performed by Digora TM system. Five radiographic density readings were performed for each studied material and for each step of the aluminum scale. RESULTS: White ProRoot MTA (155.99±8.04, gray ProRoot MTA (155.96±16.30 and MTA BIO (143.13±16.94 presented higher radiopacity values (p<0.05, while white non-structural Portland (119.76±22.34, gray Portland (109.71±4.90 and white structural Portland (99.59±12.88 presented lower radiopacity values (p<0.05. CONCLUSIONS: It was concluded that MTA-based cements were the only materials presenting radiopacity within the ANSI/ADA specifications.

This thesis is focused primarily on digitalimage processing and modern imaging modalities algorithms. An algorithm means a method for solving a problem or an instruction. In image processing an algorithm presents the process from data acquisition to the resulting image displayed on the monitor. Therefore, in the first part of the thesis a brief overview of principles of imaging modalities used in radiodiagnostics is given. Collected data have to be analyzed and modelled in a certain way. The...

This study was performed to evaluate and compare the radiopacity of dentin, enamel, and 8 restorative composites on conventional radiograph and digitalimages with different resolutions. Specimens were fabricated from 8 materials and human molars were longitudinally sectioned 1.0 mm thick to include both enamel and dentin. The specimens and tooth sections were imaged by conventional radiograph using 4 sized intraoral film and digitalimages were taken in high speed and high resolution modes using a phosphor storage plate. Densitometric evaluation of the enamel, dentin, restorative materials, a lead sheet, and an aluminum step wedge was performed on the radiographicimages. For the evaluation, the Al equivalent (mm) for each material was calculated. The data were analyzed using one-way ANOVA and Tukey's test (p<0.05), considering the material factor and then the radiographic method factor, individually. The high speed mode allowed the highest radiopacity, while the high resolution mode generated the lowest values. Furthermore, the high resolution mode was the most efficient method for radiographic differentiation between restorative composites and dentin. The conventional radiograph was the most effective in enabling differentiation between enamel and composites. The high speed mode was the least effective in enabling radiographic differentiation between the dental tissues and restorative composites. The high speed mode of digitalimaging was not effective for differentiation between enamel and composites. This made it less effective than the high resolution mode and conventional radiographs. All of the composites evaluated showed radiopacity values that fit the ISO 4049 recommendations.

Advances in MR imaging technologies, as well as the widening of their availability, boosted their use in the diagnosis of spinal disorders and in the preoperative planning of spine surgeries. However, the most consolidated approach to the assessment of adult patients with spinal disorders is based on the analysis of full standing radiographs (posteroanterior and laterolateral views). In this article, the radiographic spinal and pelvic parameters, which have relevance in the clinical management of adults with spinal disorders, are summarized.

This paper gives an overview of the requirements for, and current state-of-the-art of, CCD and CMOS imagers for use in digital still photography. Four market segments will be reviewed: mobile imaging, consumer "point-and-shoot cameras", consumer digital SLR cameras and high-end professional camera systems. The paper will also present some challenges and innovations with respect to packaging, testing, and system integration.

To compare the diagnostic performance of light emitting diode (LED) backlight monitors and cold cathode fluorescent lamp (CCFL) monitors for the interpretation of digital chest radiographs. We selected 130 chest radiographs from health screening patients. The soft copy image data were randomly sorted and displayed on a 3.5 M LED (2560 x 1440 pixels) monitor and a 3 M CCFL (2048 x 1536 pixels) monitor. Eight radiologists rated their confidence in detecting nodules and abnormal interstitial lung markings (ILD). Low dose chest CT images were used as a reference standard. The performance of the monitor systems was assessed by analyzing 2080 observations and comparing them by multi-reader, multi-case receiver operating characteristic analysis. The observers reported visual fatigue and a sense of heat. Radiant heat and brightness of the monitors were measured. Measured brightness was 291 cd/m{sup 2} for the LED and 354 cd/m{sup 2} for the CCFL monitor. Area under curves for nodule detection were 0.721 ± 0.072 and 0.764 ± 0.098 for LED and CCFL (p = 0.173), whereas those for ILD were 0.871 ± 0.073 and 0.844 ± 0.068 (p = 0.145), respectively. There were no significant differences in interpretation time (p = 0.446) or fatigue score (p = 0.102) between the two monitors. Sense of heat was lower for the LED monitor (p = 0.024). The temperature elevation was 6.7 degree C for LED and 12.4 degree C for the CCFL monitor. Although the LED monitor had lower maximum brightness compared with the CCFL monitor, soft copy reading of the digital chest radiographs on LED and CCFL showed no difference in terms of diagnostic performance. In addition, LED emitted less heat.

This paper is the first to systematically investigate computer tomography (CT) images vs. ordinary flat plane radiography for evaluating Harris Lines (HL) on tibiae. Harris Lines are traditionally investigated using radiographicimages and recorded as either present or absent, or by counting...

In the present study, we coined the term 'alveolar dome' and aimed to demonstrate the prevalence of alveolar domes through digital periapical radiographs. This study examined 800 digital periapical radiographs in regard to the presence of alveolar domes. The periapical radiographs were acquired by a digital system using a photostimulable phosphor (PSP) plate. The χ2 test, with a significance level of 5%, was used to compare the prevalence of alveolar domes in the maxillary posterior teeth and, considering the same teeth, to verify the difference in the prevalence of dome-shaped phenomena between the roots. The prevalence of alveolar domes present in the first pre-molars was statistically lower as compared to the other maxillary posterior teeth (p<0.05). No statistically significant difference was observed in the prevalence of alveolar domes between the maxillary first and second molars. Considering the maxillary first and second molars, it was observed that the palatal root presented a lower prevalence of alveolar domes when compared to the distobuccal and mesiobuccal roots (p<0.05). The present study coined the term 'alveolar dome', referring to the anatomical projection of the root into the floor of the maxillary sinus. The maxillary first and second molars presented a greater prevalence of alveolar domes, especially in the buccal roots, followed by the third molars and second pre-molars. Although the periapical radiograph is a two-dimensional method, it can provide dentists with the auxiliary information necessary to identify alveolar domes, thus improving diagnosis, planning, and treatment.

Full Text Available Introduction: Maxillary sinus floor is a part of the alveolar bone adjacent to the apex of the posterior maxillary teeth that often causes complications in dentistry. Anatomical relationship between the maxillary posterior tooth root and the maxillary sinus floor can be obtained by panoramic radiograph. The purpose of this study is to analysis digital panoramic radiograph about positions root of maxillary posterior teeth’s with maxillary sinus floor by age and gender using. Methods: Research method is descriptive with purposive sampling technique. Study population was taken from archives of patient’s digital panoramic radiograph in Radiography Installation from January to March 2016. 88 samples were obtained from 207 digital panoramic radiographs archives. Results: The result showed that type 3 was dominated by P1 (86.8% right, 88.2% left, type 2 is dominated by P2 (24.7% right, 21% left, type 1 is dominated by M2 in the right (31.2% and M1 in the left (38.1%. Conclusion: This study concludes that overall, the most commonly found was type 3. Based on the age, type 1 majority occurs in age group of above 49 years old; type 2 in age group of 40-49 years old; and type 3 in age group 30-39 years old, 40-49 years old, and above 49 years old. By gender, type 1 and type 2 are more common in males, while type 3 is more common in female.

Doses induced by individual dental examinations are low. However, dental radiography accounts for nearly one third of the total number of radiological examinations in the European Union. Therefore, special attention is needed with regard to radiation protection. In order to lower patient doses, the staff performing dental examinations must have competence in imaging as well as in radiation protection issues. This paper presents a systematic review about the core competencies needed by the healthcare staff in performing digital dental radiological imaging quality assurance. The following databases were searched: Pubmed, Cinahl, Pro Quest and IEEXplore digital library. Also volumes of some dental imaging journals and doctoral theses of the Finnish universities educating dentists were searched. The search was performed using both MeSH terms and keywords using the option 'search all text'. The original keywords were: dental imaging, digital, x-ray, panoramic, quality, assurance, competence, competency, skills, knowledge, radiographer, radiologist technician, dentist, oral hygienist, radiation protection and their Finnish synonyms. Core competencies needed by the healthcare staff performing digital dental radiological imaging quality assurance described in the selected studies were: management of dental imaging equipment, competence in image quality and factors associated with it, dose optimization and quality assurance. In the future there will be higher doses in dental imaging due to increasing use of CBCT and digitalimaging. The staff performing dental imaging must have competence in dental imaging quality assurance issues found in this review. They also have to practice ethical radiation safety culture in clinical practice.

The healing of periodontal splinting can be detected both with clinical and radiographic examination. In this study, the alveolar bone was evaluated by radiographicdigital periapical analysis. Periodontal tooth splinting is periodontal support therapy used to prevent periodontal injury during repair and regeneration of periodontal therapy. Radiographicdigital periapical analysis of alveolar bone in the mandibular anterior region with chronic periodontitis and 2/3 cervical bone loss after three months of periodontal splinting. Eighty four proximal site (43 mesial and 41 distal) from 16 patients with chronic periodontitis and treated with spinting were examined by taking periapical digitalradiographic at day 1 and 91. The bone loss, bone density and utility of lamina dura were evaluated. The statistical analysis after three months evaluation using T-test for bone loss, Wilcoxon sign rank test for bone density and utility lamina dura showed no significantly differences (pperiodontitis with 2/3 alveolar bone loss after three months splinting.

International audience; A specific field of image processing focuses on the evaluation of image quality and assessment of their authenticity. A loss of image quality may be due to the various processes by which it passes. In assessing the authenticity of the image we detect forgeries, detection of hidden messages, etc. In this work, we present an overview of these areas; these areas have in common the need to develop theories and techniques to detect changes in the image that it is not detect...

Image synthesis, or rendering, is a field of transformation: it changesgeometry and physics into meaningful images. Because the most popularalgorithms frequently change, it is increasingly important for researchersand implementors to have a basic understanding of the principles of imagesynthesis. Focusing on theory, Andrew Glassner provides a comprehensiveexplanation of the three core fields of study that come together to formdigital image synthesis: the human visual system, digital signalprocessing, and the interaction of matter and light. Assuming no more thana basic background in calculus,

The purpose of the study was to demonstrate the feasibility of a hybrid functional/anatomic breast imaging platform with biopsy capability for facilitating lesion detection and diagnosis. This platform consists of an investigative dedicated positron emission mammography (PEM) device mounted on a stereotactic X-ray mammography system, permitting sequential acquisition of mammographic and emission images during a single breast compression. There is automatic coregistration of images from both modalities, and these results can be successfully correlated with histopathologic findings. The potential utility of functional images correlated to anatomic images would include noninvasively detecting clinically and radiographically occult cancers, assessing response to therapy, discriminating between benign and malignant breast masses, and ultimately reducing the number of invasive and costly surgical interventions. A spot-digital mammogram and subsequent PEM image, collected over a 4-minute period, were obtained in a single patient with the breast in compression after intravenous injection of (F-18)-2-deoxy-2-fluoro-D-glucose (FDG) at the time of stereotactic biopsy. The authors conclude that FDG-based lesion localization information may be combined with the lesion X-ray attenuation characteristics using this common imaging platform.

This paper presents an innovative tool nationwide for the automatic analysis of the constancy of the imaging chain digitalradiographic equipment, both computed radiography (CR) and direct digital (DR).

Methods to visualize the two-dimensional distribution of molecules by mass spectrometric imaging evolve rapidly and yield novel applications in biology, medicine, and material surface sciences. Most mass spectrometric imagers acquire high mass resolution spectra spot-by-spot and thereby scan the object's surface. Thus, imaging is slow and image reconstruction remains cumbersome. Here we describe an imaging mass spectrometer that exploits the true imaging capabilities by ion optical means for the time of flight mass separation. The mass spectrometer is equipped with the ASIC Timepix chip as an array detector to acquire the position, mass, and intensity of ions that are imaged by MALDI directly from the target sample onto the detector. This imaging mass spectrometer has a spatial resolving power at the specimen of (84\\pm35) \\mu m with a mass resolution of 45 and locates atoms or organic compounds on a surface area up to ~2 cm2. Extended laser spots of ~5 mm2 on structured specimens allowed parallel imaging of s...

The aim of this study was to evaluate the performance of digital radiography in the detection of early very small erosions and joint space narrowing; in the hands and feet in rheumatoid arthritis. Fifty-three sets of film-screen and digitalradiographs of the same hands and feet with very small and

In conventional mammography, contrast sensitivity remains limited due to the superimposition of breast tissue and scattered X-rays, which induces low visibility of lesions in the breast and, thus, an excessive number of false-positive findings. Several methods, including digital breast tomosynthesis as a multiplanar imaging modality, air-gap and slot techniques for the reduction of scatters, phase-contrast imaging as another image-contrast modality, etc., have been investigated in attempt to overcome these difficulties. However, those techniques typically require a higher imaging dose or special equipment. In this work, as an alternative, we propose a new image restoration method based on a radiographic scattering model in which the intensity of scattered X-rays and the direct transmission function of a given medium are estimated from a single projection by using the dark-channel prior. We implemented the proposed algorithm and performed an experiment to demonstrate its viability. Our results indicate that most of the structures in the examined breast were very discernable even with no adjustment in the display-window level, thus preserving superior image features and edge sharpening.

To compare CT and radiographicimages of the lungs in sedated healthy foals positioned in sternal recumbency and to investigate whether a relationship exists between CT-derived measurements of lung attenuation and Paco2 and Pao2. 6 healthy Standardbred foals < 14 days of age. Thoracic CT images were acquired followed by radiographic views with each foal sedated and positioned in sternal recumbency. For each foal, both CT and radiographicimages were evaluated for severity and extent of changes by lung regions on the basis of a subjective scoring system by 3 investigators. Quantitative analysis of CT images was also performed. Assessments of Pao2 and Paco2 were performed before sedation, following sedation prior to CT, and after CT prior to radiography. Interobserver agreement for CT and radiographicimage scoring was strong (0.73) and fair (0.65), respectively; intraobserver agreement was near perfect for CT (0.97) and radiographic (0.94) image scoring. Increased CT attenuation and radiographic changes were identified for all foals and were preferentially distributed in the caudoventral portion of the lungs. Radiographic scores were significantly lower than CT image scores. A positive correlation (r = 0.872) between lung attenuation and CT image score was identified. A significant increase in Paco2 was not considered clinically relevant. Significant changes in Pao2 were not observed. Results suggested that interpretation of CT images may be less subjective, compared with interpretation of radiographicimages. These findings may aid in the evaluation of CT and radiographicimages of neonatal foals with respiratory tract disease.

Purpose: To describe the magnetic resonance imaging (MRI) findings in retropharyngeal tendinitis. Material and methods: Within 1 year, four patients presenting with symptoms of retropharyngeal tendinitis were examined by radiography and MRI. Results: On MRI and radiographs, all patients had characteristic soft-tissue swellings and calcifications related to the tendon of the longus colli muscle situated inferior to the anterior arc of C1. MRI showed well-defined edema, with high signal in the retropharyngeal tissue anterior to C1-C5 on short T1 inversion recovery (STIR) sequences, low signal on T1-weighted sequences, and low signal in the calcification on both sequences. In addition, three patients had high signal intensity changes on STIR sequences in the atlantoaxial joint situated posterior to the anterior arc of C1. Conclusion: MRI is a sensitive and accurate method in the diagnosis of retropharyngeal tendinitis. A new finding in this condition is an effusion or synovitis in the anterior atlantoaxial joint. MRI is a valuable tool in differentiating retropharyngeal tendinitis from other diagnoses such as retropharyngeal abscess, pyogenic spondylitis, and spondyloarthropathy.

Endovascular and percutaneous techniques have emerged as alternatives to surgical management in the treatment for a wide range of congenital and acquired cardiac, non-vascular and vascular conditions. Consequently, there has been an increasing use of implants such as closure devices, vascular stents (coronary, aortic, pulmonary and superior vena cava) and non-vascular stents like oesophageal and tracheo-bronchial stents. A large number of percutaneously sited implants are used for treating congenital cardiac anomalies such as atrial septal defects (ASD), ventricular septal defects (VSD), and patent ductus arteriosus (PDA). These implants take many shapes and forms. The aim of this review is to demonstrate the radiographic appearances of the various types of cardiovascular, bronchial and oesophageal implants that are visible on plain films. A brief outline of the aims and indications of various implant procedures, the general appearance of the commonest types of implants, and the radiological procedures are discussed. All radiologists are likely to come across implanted devices in plain film reporting. Imaging can be useful in identifying the device, assessing the position, integrity, and for the identification of complications related directly to the implant.

A prototype digitalimage processor for enhancing photographic images has been built in the Research Laboratories at Kodak. This image processor implements a particular version of each of the following algorithms: photographic grain and noise removal, edge sharpening, multidimensional image-segmentation, image-tone reproduction adjustment, and image-color saturation adjustment. All processing, except for segmentation and analysis, is performed by massively parallel and pipelined special-purpose hardware. This hardware runs at 10 MHz and can be adjusted to handle any size digitalimage. The segmentation circuits run at 30 MHz. The segmentation data are used by three single-board computers for calculating the tonescale adjustment curves. The system, as a whole, has the capability of completely processing 10 million three-color pixels per second. The grain removal and edge enhancement algorithms represent the largest part of the pipelined hardware, operating at over 8 billion integer operations per second. The edge enhancement is performed by unsharp masking, and the grain removal is done using a collapsed Walsh-hadamard transform filtering technique (U.S. Patent No. 4549212). These two algo-rithms can be realized using four basic processing elements, some of which have been imple-mented as VLSI semicustom integrated circuits. These circuits implement the algorithms with a high degree of efficiency, modularity, and testability. The digital processor is controlled by a Digital Equipment Corporation (DEC) PDP 11 minicomputer and can be interfaced to electronic printing and/or electronic scanning de-vices. The processor has been used to process over a thousand diagnostic images.

The study aimed to compare the sensitivity and specificity of digitalradiographic systems for the diagnosis of proximal carious lesions. Extracted human teeth (3 canines, 3 premolars, and 3 molars) were submitted to one of three types of proximal lesions (demineralized area, cavity affecting the enamel alone, and cavity affecting enamel and dentin). Bitewing radiographs were obtained from each system (Sirona, Kodak, and Schick) and evaluated by 12 raters (4 dental students, 4 radiology specialists, and 4 dentists). The chi-squared test was used to determine the frequency of correct diagnoses among the different systems, raters, teeth, and types of lesion. Sensitivity and specificity regarding demineralized areas were calculated for each system. The frequencies of correct diagnoses were found: Schick (70.8%), Kodak (63.9%), Sirona (59.0%), specialists (69.4%), students (62.5%), dentists (61.8%), premolars (70.1%), canines (65.3%), and molars (58.3%). No significant differences were found among the different systems, raters, or teeth (P > 0.05). Sensitivity and specificity were 0.64 and 0.47 (Schick), 0.56 and 0.50 (Sirona), and 0.48 and 0.58 (Kodak). The most correct diagnoses were achieved using the Schick digital system on premolars and evaluated by specialists in radiology. The systems demonstrated low sensitivity and specificity for the diagnosis of demineralized areas.

Conclusion: Meniscal subluxation is a prominent feature on weight-bearing sonographic imaging in patients with radiographic osteoarthritis and could be considered as a risk factor for the development of knee osteoarthritis. By using musculoskeletal ultrasonography, one can detect this occult meniscal derangement early before the appearance of radiographic signs of osteoarthritis.

The ability to access a vast array of radiological and pathologic diagnoses through computer searches of local medical facility databases is a by-product of the continued development of filmless imaging systems. The Department of Defense (DoD) Medical Diagnostic Imaging Support initiative is expanding through the addition of on-line systems at several DoD health care facilities. Madigan Army Medical Center, as the initial site, will soon be 90% filmless, with over one million images archived. Multiple other DoD medical centers are under installation. The eventual goal is an interconnected network of PACS systems of DoD medical centers and their supported medical facilities throughout the United States. To access this potential pool of medical information requires a centralized database capable of acting as a diagnostic index system. The establishment of a multi-center film library index begins with an initial analysis of issues regarding data storage and access, indexing, cross-coding with pathological files, communication formats, cost sharing, and patient confidentiality. In initiating these first steps to developing this telecommunications library these issues and their implications are discussed. The final implementation of this system will facilitate markedly improved research and teaching capabilities in both radiological and pathological fields.

There has been an increasing demand for low cost, portable CMOS image sensors because of increased integration, and new applications in the automotive, mobile communication and medical industries, amongst others. Colour reproduction remains imperfect in conventional digitalimage sensors, due to the limitations of the dye-based filters. Further improvement is required if the full potential of digitalimaging is to be realised. In alternative systems, where accurate colour reproduction is a priority, existing equipment is too bulky for anything but specialist use. In this work both these issues are addressed by exploiting nanophotonic techniques to create enhanced trichromatic filters, and multispectral filters, all of which can be fabricated on-chip, i.e. integrated into a conventional digitalimage sensor, to create compact, low cost, mass produceable imaging systems with accurate colour reproduction. The trichromatic filters are based on plasmonic structures. They exploit the excitation of surface plasmon resonances in arrays of subwavelength holes in metal films to filter light. The currently-known analytical expressions are inadequate for optimising all relevant parameters of a plasmonic structure. In order to obtain arbitrary filter characteristics, an automated design procedure was developed that integrated a genetic algorithm and 3D finite-difference time-domain tool. The optimisation procedure's efficacy is demonstrated by designing a set of plasmonic filters that replicate the CIE (1931) colour matching functions, which themselves mimic the human eye's daytime colour response.

Full Text Available This work aimed to evaluate the occurrence of suggestive images of styloid process elongation in panoramic radiographs, noting their frequency according to sex, age, and location, as well as measure and classify the types and patterns of calcification of elongated styloid processes. 2,500 panoramic radiographs were evaluated in a Radiology Clinic in Recife, PE, Brazil, performed between 2008 and 2010, with the age ranging from 25 to 80 years old. 560 of the radiographs analyzed fulfilled the inclusion criteria. Of this total, 216 (38.57% presented suggestive images of the styloid process elongation, 45 (20.8% belonging to male and 171 (79.2% to female, and 84.7% were bilateral. After all measurements, mean values of 35.5 mm (left side and 37.6 mm (right side were obtained and these differences were statistically significant (p<0.001. The most common type of stretching found was elongated (type I with 73.1%, and the pattern of calcification was partially calcified (62.5%. It was found that the elongation of the styloid process is an anatomical variation, which must be taken into account by dentists, and because panoramic radiography is a technique of easy approach and low cost and routine, it can be used to aid in the diagnosis of elongated styloid process.

To evaluate the reliability of the digitalradiograph of the middle phalanx of the third finger (MP3) in skeletal maturity assessment. Fifty children (24 girls and 26 boys) belonging to the circumpubertal age-group were selected for the study. Two radiographs - lateral cephalogram and digitalradiograph of the MP3 region - were taken in each child. Age assessment was based on the changes in shape of the cervical vertebrae and the epiphysis of the middle phalanx of the third finger of the left hand. The radiographs were assessed by three examiners. The inter- and intraexaminer variability were determined by the Wilcoxon rank sign test and the Kruskal-Wallis test and were found to be nonsignificant. Examiner 3 showed the best intraexaminer agreement and was selected to evaluate the radiographs for the entire study. The correlation determined between the MP3 stages and cervical vertebrae maturity index (CVMI) stages, the peak-wise distribution of the MP3 stages, and the correlation between the MP3 stages and the chronological age were found to be highly significant. Digitalradiograph of the MP3 region is definitely a simple, reliable, cost-effective, and time-saving technique for the assessment of skeletal maturity.

Bioceramics have been adopted in dental restorations for implants, bridges, inlays, onlays, and all-ceramic crowns. Dental bioceramics include glass ceramics, reinforced porcelains, zirconias, aluminas, fiber-reinforced ceramic composites, and multilayered ceramic structures. The process of additive manufacturing is ideally suited to dentistry. Models are designed using data from a computed tomography scan or magnetic resonance imaging. Since its development in 2001, direct ceramic machining of presintered yttria tetragonal zirconia polycrystal has become increasingly popular in dentistry. There are wide variety commercially available cements for luting all-ceramic restorations. However, resin cements have lower solubility and better aesthetic characteristics.

Aims: The aim of this study was to: (1) compare the diagnostic accuracy of the high-resolution and standard resolution settings of four digitalimaging systems for caries diagnosis and (2) compare the effect on the diagnostic accuracy of reducing the high-resolution image sizes to the standard

To determine whether digital signature technology (DST) can authenticate digital medical images to the same level of authenticity required for interbank electronic transfer of funds. Message digests were computed for two magnetic resonance images that differed only by the value of a single bit. RSA (Rivest, Shamir, and Adleman) public key cryptography was used to encrypt each message digest to form a digital signature for each image, a process analogous to the established use of RSA DST for electronic funds transfer. The process was then reversed to authenticate the original image from its digital signature. Although the images differed by less than 0.000095%, their message digests differed at 94% of their characters. The digital signature of the original image proved that it was authentic and that the altered image was not authentic. RSA DST can establish the authenticity of images to at least the level of confidence required for interbank electronic transfer of funds.

The Advance Radiographic Capability (ARC) at the National Ignition Facility (NIF) is a laser system that employs up to four petawatt (PW) lasers to produce a sequence of short-pulse kilo-Joule laser pulses with controllable delays that generate X-rays to provide backlighting for high-density internal confinement fusion (ICF) capsule targets. Multi-frame, hard-X-ray radiography of imploding NIF capsules is a capability which is critical to the success of NIF's missions. ARC is designed to employ up to eight backlighters with tens-of-picosecond temporal resolution, to record the dynamics and produce an X-ray "motion picture" of the compression and ignition of cryogenic deuterium-tritium targets. ARC will generate tens-of-picosecond temporal resolution during the critical phases of ICF shots. Additionally, ARC supports a variety of other high energy density experiments including fast ignition studies on NIF. The automated alignment image analysis algorithms use digital camera sensor images to direct ARC beams onto the tens-of-microns scale metal wires. This paper describes the ARC automatic alignment sequence throughout the laser chain from pulse initiation to target with an emphasis on the image processing algorithms that generate the crucial alignment positions for ARC. The image processing descriptions and flow diagrams detail the alignment control loops throughout the ARC laser chain beginning in the ARC high-contrast front end (HCAFE), on into the ARC main laser area, and ending in the ARC target area.

Objective To evaluate and reduce inter-observer variations in the detection and characterization of pulmonary nodules on digitalradiograph (DR) chest images.Methods Two hundreds and thirty-two new posterior-anterior DR chest images were collected from out-patient screening patients. Consensus was reached by two experienced radiologists on the marking, rating, and segmentation of small actionable nodules ranged from 5 to 15 mm in diameter using a computer-aided diagnosis (CAD) system. Both their own nodule findings and the computer's automatic nodule detection results were analyzed to make the consensus.Nodules identified together with corresponding likelihood rating and segmentation results were referred as "Gold Standard". Two un-experienced radiologists were asked to first mark and characterize suspicious nodules independently, then were allowed to consult the computer nodule detection results and change their decisions.Results Large inter-observer variations in pulmonary nodule identification and characterization on DR chest images were observed between un-experienced radiologists. Un-experienced radiologists could greatly benefit from the CAD system, including substantial decrease of inter-observer variation and improvement of nodule detection rates. Moreover,radiologists with different levels of skillfulness could achieve similar high level performance after using the CAD system.Conclusion The CAD system shows a high potential for providing a valuable assistance to the examination of DR chest images.

This paper investigates the requirements for image processing of digital chest X-ray images. These images are conventionally recorded on film and are characterised by large size, wide dynamic range and high resolution. X-ray detection systems are now becoming available for capturing these images directly in photoelectronic-digital form. The hardware and software facilities required for handling these images are described. These facilities include high resolution digitalimage displays, programmable video look up tables, image stores for image capture and processing and a full range of software tools for image manipulation. Examples are given of the applications of digitalimage processing techniques to this class of image.

Full Text Available There exist several methods for calculating the fractal dimension of objects represented as 2D digitalimages. For example, Box counting, Minkowski dilation or Fourier analysis can be employed. However, there appear to be some limitations. It is not possible to calculate only the fractal dimension of an irregular region of interest in an image or to perform the calculations in a particular direction along a line on an arbitrary angle through the image. The calculations must be made for the whole image. In this paper, a new method to overcome these limitations is proposed. 2D images are appropriately prepared in order to apply 1D signal analyses, originally developed to investigate nonlinear time series. The Higuchi dimension of these 1D signals is calculated using Higuchi's algorithm, and it is shown that both regions of interests and directional dependencies can be evaluated independently of the whole picture. A thorough validation of the proposed technique and a comparison of the new method to the Fourier dimension, a common two dimensional method for digitalimages, are given. The main result is that Higuchi's algorithm allows a direction dependent as well as direction independent analysis. Actual values for the fractal dimensions are reliable and an effective treatment of regions of interests is possible. Moreover, the proposed method is not restricted to Higuchi's algorithm, as any 1D method of analysis, can be applied.

This paper features an advanced implementation of the X-ray rendering algorithm that harnesses the giant computing power of the current commodity graphics processors to accelerate the generation of high resolution digitally reconstructed radiographs (DRRs). The presented pipeline exploits the latest features of NVIDIA Graphics Processing Unit (GPU) architectures, mainly bindless texture objects and dynamic parallelism. The rendering throughput is substantially improved by exploiting the interoperability mechanisms between CUDA and OpenGL. The benchmarks of our optimized rendering pipeline reflect its capability of generating DRRs with resolutions of 2048(2) and 4096(2) at interactive and semi interactive frame-rates using an NVIDIA GeForce 970 GTX device.

The application of digital processing techniques to spacecraft television pictures and radar images is discussed. The use of digital rectification to produce contour maps from spacecraft pictures is described; images with azimuth and elevation angles are converted into point-perspective frame pictures. The digital correction of the slant angle of radar images to ground scale is examined. The development of orthophoto and stereoscopic shaded relief maps from digital terrain and digitalimage data is analyzed. Digitalimage transformations and rectifications are utilized on Viking Orbiter and Lander pictures of Mars.

In the past decade various museums and galleries around Europe have been developing digitalimaging as a tool for archiving and analysis. Accurate digitalimages can replace the conventional film archives which are not stable or accurate but are the standard record of art. The digital archives open up new research possibilities as well as become resources for CD- ROM production, damage analysis, research and publishing. In the VASARI project new scanners were devised to produce colorimetric images directly from paintings using multispectral (six band) imaging. These can produce images in CIE Lab format with resolutions over 10 k multiplied by 10 k and have been installed in London, England; Munich, Germany; and Florence, Italy. They are based around a large stepper-motor controlled scanner moving a high resolution CCD camera to obtain patches of 3 k multiplied by 2 k pels which are mosaiced together. The scanners can also be used for infra-red imaging with a different camera. The MARC project produced a portable scan-back, RGB camera capable of similar output and techniques for calibrated printing. The Narcisse project produced a fast high resolution scanner for X-radiographs and film and many projects have worked on networking the growing number of image databases. This paper presents a survey of some key European projects, particularly those funded by the European Union, involved in high resolution and colorimetric imaging of art. The design of the new scanners and examples of the applications of these images are presented.

Bone age assessment is a procedure performed in pediatric patients to quickly evaluate parameters of maturation and growth from a left hand and wrist radiograph. Pietka and Cao have developed a Computer-aided diagnosis (CAD) method of bone age assessment based on a digital hand atlas. The aim of this paper is to extend their work by automatically select the best representative image from a group of normal children based on specific bony features that reflect skeletal maturity. The group can be of any ethnic origin and gender from one year to 18 year old in the digital atlas. This best representative image is defined as the "average" image of the group that can be augmented to Piekta and Cao's method to facilitate in the bone age assessment process.

The aim of this study was to evaluate the performance of digital radiography in the detection of early very small erosions and joint space narrowing in the hands and feet in rheumatoid arthritis. Fifty-three sets of film-screen and digitalradiographs of the same hands and feet with very small and sometimes questionable lesions (possible erosions and cysts) were scored independently two times by four investigators. The percentage of lesions found in exactly the same position for each investigator was calculated. Intra-observer agreement between first and second reading in film-screen radiography was 64-76 % (mean 67 %), and in digitalradiographs 60-71 % (mean 64 %). Agreement between film-screen and digitalradiographs ranged from 54 to 64 % (mean 58 %) in the first reading and from 56 to 66 % (mean 62 %) in the second reading. Overall agreement between both techniques between first and second reading ranged between 62 and 73 % (mean 65 %). Digital radiography of the hands and feet can be used in patients suspected of rheumatoid arthritis and in follow-up of those patients, because small and early erosions can be seen equally well with the digital technique as compared with the conventional film-screen technique. (orig.)

The aim of this study was to evaluate the performance of digital radiography in the detection of early very small erosions and joint space narrowing in the hands and feet in rheumatoid arthritis. Fifty-three sets of film-screen and digitalradiographs of the same hands and feet with very small and sometimes questionable lesions (possible erosions and cysts) were scored independently two times by four investigators. The percentage of lesions found in exactly the same position for each investigator was calculated. Intra-observer agreement between first and second reading in film-screen radiography was 64-76 % (mean 67 %), and in digitalradiographs 60-71 % (mean 64 %). Agreement between film-screen and digitalradiographs ranged from 54 to 64 % (mean 58 %) in the first reading and from 56 to 66 % (mean 62 %) in the second reading. Overall agreement between both techniques between first and second reading ranged between 62 and 73 % (mean 65 %). Digital radiography of the hands and feet can be used in patients suspected of rheumatoid arthritis and in follow-up of those patients, because small and early erosions can be seen equally well with the digital technique as compared with the conventional film-screen technique.

In today's world several image manipulation software's are available. Manipulation of digitalimages has become a serious problem nowadays. There are many areas like medical imaging, digital forensics, journalism, scientific publications, etc, where image forgery can be done very easily. To determine whether a digitalimage is original or doctored is a big challenge. To find the marks of tampering in a digitalimage is a challenging task. The detection methods can be very useful in image forensics which can be used as a proof for the authenticity of a digitalimage. In this paper we propose the method to detect region duplication forgery by dividing the image into overlapping block and then perform searching to find out the duplicated region in the image.

DigitalImage Correlation (DIC) is a powerful technique which is used to correlate two image segments to determine the similarity between them. A correlation image is formed which gives a peak known as correlation peak. If the two image segments are identical the peak is known as auto-correlation peak otherwise it is known as cross correlation peak. The location of the peak in a correlation image gives the relative displacement between the two image segments. Use of DIC for in-plane displacement and deformation measurements in Electronic Speckle Photography (ESP) is well known. In ESP two speckle images are correlated using DIC and relative displacement is measured. We are presenting background review of ESP and disclosing a technique based on DIC for improved relative measurements which we regard as the improved DIC method. Simulation and experimental results reveal that the proposed improved-DIC method is superior to the conventional DIC method in two aspects, in resolution and in the availability of reference position in displacement measurements.

The increased use of digital processing techniques in Medical Radiations imaging modalities, along with the rapid advance in information technology has resulted in a significant change in the delivery of radiographic teaching programs. This paper details a methodology used to concurrently educate radiographers in both computer programming and image processing. The students learn to program in visual basic applications (VBA), and the programming skills are contextualised by requiring the students to write a digital subtraction angiography (DSA) package. Program code generation and image presentation interface is undertaken by the spreadsheet Microsoft Excel. The user-friendly nature of this common interface enables all students to readily begin program creation. The teaching of programming and image processing skills by this method may be readily generalised to other vocational fields where digitalimage manipulation is a professional requirement.

and digitized aerial photographs. However, it was not until the launch of Landsat - 1 in 1972 that digitalimage data became widely available for land remote sensing applications. Today with the availability of efficient computer hardware and software...

This study was performed with PA thorax examinations of adult patients performed with CR equipment in a clinic of Pato Branco, Parana state, Brazil. The values of K{sub a,E} were estimated from irradiation parameters and the yield of X ray tube. The absorbed doses in organs and tissues of patients, and the effective risks of cancer incidence were estimated by using the CALDose{sub X}-3.5 computer program. The image quality was evaluated base on criteria established by European Community. The third quartile of the K{sub a,}E estimated was 0.170 mGy, lower than the reference level established by the Brazilian Ministry of Health. The organs that presented the largest absorbed doses were: lungs (36+-16 micron Gy), kidneys (25+-14 micron Gy) and spleens (23.2+- micron Gy). The incidence of of cancer was of 0.098+-0.051 for case of 100,000 exposed persons. All the image evaluated obtained conformity over 85% of the european quality criteria

This paper is aimed at presenting a renovated model-building method of transfer function for industrial X-ray digital radiography based on the amorphous silicon X-ray flat-panel detector. The system, known as point-spreading function (PSF), is composed of three parts: the system geometrical dispersion with a non-spot power source, the scintillating screen dispersion and the aperture sampling of the pixel detector. For the innovation purpose, we have first of all established a mathematical simulation of the PSF and the modulation transfer function (MTF) on the basis of analyzing the intensity distribution of X-ray penetration area in each part and by taking Gaussian functions as a mathematical equation for depicting the transfer behavior of each part of the system. And, then, we have worked out the approximately effective bandwidth of the system from its half-wave width. And, finally, by taking the digital radiography based on the flat-panel detector for sampling, the paper has provided a theoretical foundation for the industrial X-ray radiographic testing and measurement operation. In addition, the author has also estimated the validation of the model through experiments and proved that the method helps to make high resolutions of the diacritical tiniest details in the work-pieces, which has shown and will show its technical rationality, technical appropriateness and practical working value.

This authoritative text (the second part of a complete MSc course) provides mathematical methods required to describe images, image formation and different imaging systems, coupled with the principle techniques used for processing digitalimages. It is based on a course for postgraduates reading physics, electronic engineering, telecommunications engineering, information technology and computer science. This book relates the methods of processing and interpreting digitalimages to the 'physics' of imaging systems. Case studies reinforce the methods discussed, with examples of current research

OBJECTIVE. The purpose of this study is to determine whether radiographic foot measurements can predict injury of the posterior tibial tendon (PTT) and the supporting structures of the medial longitudinal arch as diagnosed on MRI. MATERIALS AND METHODS. After institutional review board approval, 100 consecutive patients with radiographic and MRI examinations performed within a 2-month period were enrolled. Thirty-one patients had PTT dysfunction clinically, and 69 patients had other causes of ankle pain. Talonavicular uncoverage angle, incongruency angle, calcaneal pitch angle, Meary angle, cuneiform-to-fifth metatarsal height, and talar tilt were calculated on standing foot or ankle radiographs. MRI was used to assess for abnormalities of the PTT (tenosynovitis, tendinosis, and tear) and supporting structures of the medial longitudinal arch (spring ligament, deltoid ligament, and sinus tarsi). Statistical analysis was performed using the chi-square and Fisher exact tests for categoric variables; the Student t test was used for continuous variables. RESULTS. There was a statistically significant association of PTT tear with abnormal talonavicular uncoverage angle, calcaneal pitch angle, Meary angle, and cuneiform-to-fifth metatarsal height. PTT tendinosis and isolated tenosynovitis had a poor association with most radiologic measurements. If both calcaneal pitch and Meary angles were normal, no PTT tear was present. An abnormal calcaneal pitch angle had the best association with injury to the supporting medial longitudinal arch structures. CONCLUSION. Radiographic measurements, especially calcaneal pitch and Meary angles, can be useful in detecting PTT tears. Calcaneal pitch angle provides the best assessment of injury to the supporting structures of the medial longitudinal arch.

An application of high energy physics instrumentation is to look for structure or different densities (materials) hidden in a matrix (tons) of material. By tracing muons produced by primary Cosmic Rays, it has been possible to generate a kind of radiographs which shows the inner structure of dense containers, monuments or mountains. In this paper I review the basics principles of such techniques with emphasis in the Sun Pyramid project, carried out by IFUNAM in collaboration with Instituto Nacioanal de Antropologia e Historia.

Full Text Available Since the discovery of x-rays in 1895, film has been the primary medium for capturing, displaying and storing radiographicimages. Digital or filmless radiography is slowly being adopted by the dental profession. Digital radiography offers a number of capabilities compared with conventional radiography, such as postprocessing, electronic archiving, concurrent access to images, and improved data distribution. Computer based applications which are used for quantitative measurements and evaluations on digitalimages for better user interpretation. New diagnostic imaging processes are improved connected with the technological progress of computer systems. Since the first clinical use of computed tomography (CT scans in 1972, technological development has been rapid. Dental volumetric tomography (DVT, uniquely used for dentomaxillofacial imaging came to the market owing to recent rapid developments in digital radiology technology and is becoming more popular in dental applications. Low radiation dose cone beam computed tomography (CBCT units that are commercially available at a lower cost than CT units, has performed valuable diagnostic information for dentists. [Archives Medical Review Journal 2013; 22(2.000: 230-238

The majority of published papers deal mainly with prevalence, pathogenesis and treatment of squamous cell carcinoma of the gingiva (SCCG). On the other hand, little is discussed about the comparison between periodontal disease and gingival carcinoma with emphasis on radiographicimaging. In this case report we discuss the importance of the radiographic aspects in inflammatory periodontal disease and SCCG. This case report shows the importance of differentiating a localized severe periodontal ...

In this case, we investigated the modified license plates. The evidences had new embossing pressed serial numbers after erasing the original numbers on the license plates by hammering. The X-ray radiograph could visualize the hidden figures; those were virtually unseen by naked eyes or undetectable by ordinary photography. To reveal the erased figures, we performed image processing with computer software after X-ray radiographs. It proved to be an efficient nondestructive way to visualize the hidden original figures on metals.

The thesis describes an advanced digital solution to mining digitalimage monitor system, which makes up the shortage of the traditional mining analog image monitor. It illustrates the system components and how to choose the encoder bandwidth of the system. The problem of image multicast and its solution in LAN are also discussed.

Full Text Available The degree of imperceptibility of hidden image in the ‘DigitalImage Steganography’ is mostly defined in relation to the limitation of Human Visual System (HVS, its chances of detection using statistical methods and its capacity to hide maximum information inside its body. Whereas, a tradeoff does exist between data hiding capacity of the cover image and robustness of underlying information hiding scheme. This paper is an exertion to underline the technique to embed information inside the cover at Stego key dependent locations, which are hard to detect, to achieve optimal security. Hence, it is secure under worst case scenario where Wendy is in possession of the original image (cover agreed upon by Alice and Bob for their secret communication. Reliability of our proposed solution can be appreciated by observing the differences between cover, preprocessed cover and Stego object. Proposed scheme is equally good for color as well as gray scaled images. Another interesting aspect of this research is that it implicitly presents fusion of cover and information to be hidden in it while taking care of passive attacks on it.

Juvenile idiopathic arthritis is the most common autoimmune systemic disease of the connective tissue affecting individuals at the developmental age. Radiography is the primary modality employed in the diagnostic imaging in order to identify changes typical of this disease entity and rule out other bone-related pathologies, such as neoplasms, posttraumatic changes, developmental defects and other forms of arthritis. The standard procedure involves the performance of comparative joint radiographs in two planes. Radiographic changes in juvenile idiopathic arthritis are detected in later stages of the disease. Bone structures are assessed in the first place. Radiographs can also indirectly indicate the presence of soft tissue inflammation (i.e. in joint cavities, sheaths and bursae) based on swelling and increased density of the soft tissue as well as dislocation of fat folds. Signs of articular cartilage defects are also seen in radiographs indirectly - based on joint space width changes. The first part of the publication presents the classification of juvenile idiopathic arthritis and discusses its radiographicimages. The authors list the affected joints as well as explain the spectrum and specificity of radiographic signs resulting from inflammatory changes overlapping with those caused by the maturation of the skeletal system. Moreover, certain dilemmas associated with the monitoring of the disease are reviewed. The second part of the publication will explain issues associated with ultrasonography and magnetic resonance imaging, which are more and more commonly applied in juvenile idiopathic arthritis for early detection of pathological features as well as the disease complications.

Full Text Available Juvenile idiopathic arthritis is the most common autoimmune systemic disease of the connective tissue affecting individuals at the developmental age. Radiography is the primary modality employed in the diagnostic imaging in order to identify changes typical of this disease entity and rule out other bone-related pathologies, such as neoplasms, posttraumatic changes, developmental defects and other forms of arthritis. The standard procedure involves the performance of comparative joint radiographs in two planes. Radiographic changes in juvenile idiopathic arthritis are detected in later stages of the disease. Bone structures are assessed in the first place. Radiographs can also indirectly indicate the presence of soft tissue inflammation (i.e. in joint cavities, sheaths and bursae based on swelling and increased density of the soft tissue as well as dislocation of fat folds. Signs of articular cartilage defects are also seen in radiographs indirectly – based on joint space width changes. The first part of the publication presents the classification of juvenile idiopathic arthritis and discusses its radiographicimages. The authors list the affected joints as well as explain the spectrum and specificity of radiographic signs resulting from inflammatory changes overlapping with those caused by the maturation of the skeletal system. Moreover, certain dilemmas associated with the monitoring of the disease are reviewed. The second part of the publication will explain issues associated with ultrasonography and magnetic resonance imaging, which are more and more commonly applied in juvenile idiopathic arthritis for early detection of pathological features as well as the disease complications.

In picture archiving and communications systems (PACS), images need to be displayed in standardized ways for radiologists' interpretations. However, for most radiographs acquired by computed radiography (CR), digital radiography (DR), or digitized films, the image orientation is undetermined because of the variation of examination conditions and patient situations. To address this problem, an automatic orientation correction method is presented. It first detects the most indicative region for orientation in a radiograph, and then extracts a set of low-level visual features sensitive to rotation from the region. Based on these features, a trained classifier based on a support vector machine is employed to recognize the correct orientation of the radiograph and reorient it to a desired position. A large-scale experiment has been conducted on more than 12,000 radiographs covering a large variety of body parts and projections to validate the method. The overall performance is quite promising, with the success rate of orientation correction reaching 95.2%.

The National Screening Committee has stated that “All people with diabetes aged 12 years and older should be offered screening for sight-threatening diabetic retinopathy using digital photography.”1 Digitalimaging offers several advantages such as archiving, ease of viewing evidence of progression, quality assurance, patient education and immediate indication of ungradable images. Knowledge of key aspects of digitalimaging technology and performance therefore underpin screening for diabetic...

The photomosaic that forms the base for this globe was created by merging two global digitalimage models (DIM's) of Mars-a medium-resolution monochrome mosaic processed to emphasize topographic features and a lower resolution color mosaic emphasizing color and albedo variations.The medium-resolution (1/256 or roughly 231 m/pixel) monochromatic image model was constructed from about 6,000 images having resolutions of 150-350 m/pixel and oblique illumination (Sun 20 o -45 o above the horizon). Radiometric processing was intended to suppress or remove the effects of albedo variations through the use of a high-pass divide filter, followed by photometric normalization so that the contrast of a given topographic slope would be approximately the same in all images.The global color mosaic was assembled at 1/64 or roughly 864 m/pixel from about 1,000 red- and green-filter images having 500-1,000 m/pixel resolution. These images were first mosaiced in groups, each taken on a single orbit of the Viking spacecraft. The orbit mosaics were then processed to remove spatially and temporally varying atmospheric haze in the overlap regions. After haze removal, the per-orbit mosaics were photometrically normalized to equalize the contrast of albedo features and mosaiced together with cosmetic seam removal. The medium-resolution DIM was used for geometric control of this color mosaic. A green-filter image was synthesized by weighted averaging of the red- and violet-filter mosaics. Finally, the product seen here was obtained by multiplying each color image by the medium-resolution monochrome image. The color balance selected for images in this map series was designed to be close to natural color for brighter, redder regions, such as Arabia Terra and the Tharsis region, but the data have been stretched so that the relatively dark regions appear darker and less red than they actually are.The images are presented in a projection that portrays the entire surface of Mars in a manner

The problem of storing, transmitting, and manipulating digitalimages is considered. Because of the file sizes involved, large amounts of digitizedimage information are becoming common in modern projects. Our goal is to described an image compression transform coder based on artificial neural networks techniques (NNCTC). A comparison of the compression results obtained from digital astronomical images by the NNCTC and the method used in the compression of the digitized sky survey from the Space Telescope Science Institute based on the H-transform is performed in order to assess the reliability of the NNCTC.

3D imaging technique is very important and indispensable in diagnosis. The main stream of the technique is one in which 3D image is reconstructed from a set of slice images, such as X-ray CT and MRI. However, these systems require large space and high costs. On the other hand, a low cost and small size 3D imaging system is needed in clinical veterinary medicine, for example, in the case of diagnosis in X-ray car or pasture area. We propose a novel 3D imaging technique using 2-D X-ray radiographicimages. This system can be realized by cheaper system than X-ray CT and enables to get 3D image in X-ray car or portable X-ray equipment. In this paper, a 3D visualization technique from 2-D radiographicimages is proposed and several reconstructions are shown. These reconstructions are evaluated by veterinarians.

This study aims to explore the classification ability of decision trees (DTs) and support vector machines (SVMs) to discriminate between the digital chest radiographs (DRs) of pneumoconiosis patients and control subjects. Twenty-eight wavelet-based energy texture features were calculated at the lung fields on DRs of 85 healthy controls and 40 patients with stage I and stage II pneumoconiosis. DTs with algorithm C5.0 and SVMs with four different kernels were trained by samples with two combinations of the texture features to classify a DR as of a healthy subject or of a patient with pneumoconiosis. All of the models were developed with fivefold cross-validation, and the final performances of each model were compared by the area under receiver operating characteristic (ROC) curve. For both SVM (with a radial basis function kernel) and DT (with algorithm C5.0), areas under ROC curves (AUCs) were 0.94 ± 0.02 and 0.86 ± 0.04 (P = 0.02) when using the full feature set and 0.95 ± 0.02 and 0.88 ± 0.04 (P = 0.05) when using the selected feature set, respectively. When built on the selected texture features, the SVM with a polynomial kernel showed a higher diagnostic performance with an AUC value of 0.97 ± 0.02 than SVMs with a linear kernel, a radial basis function kernel and a sigmoid kernel with AUC values of 0.96 ± 0.02 (P = 0.37), 0.95 ± 0.02 (P = 0.24), and 0.90 ± 0.03 (P = 0.01), respectively. The SVM model with a polynomial kernel built on the selected feature set showed the highest diagnostic performance among all tested models when using either all the wavelet texture features or the selected ones. The model has a good potential in diagnosing pneumoconiosis based on digital chest radiographs.

We have collected a digital hand atlas containing digitized left hand radiographs of normally developed children grouped accordingly by age, sex, and race. A set of features stored in a database reflecting patient's stage of skeletal development has been calculated by automatic image processing procedures. This paper addresses a new concept, "average" image in the digital hand atlas. The "average" reference image in the digital atlas is selected for each of the groups of normal developed children with the best representative skeletal maturity based on bony features. A data mining procedure was designed and applied to find the average image through average feature vector matching. It also provides a temporary solution for the missing feature problem through polynomial regression. As more cases are added to the digital hand atlas, it can grow to provide clinicians accurate reference images to aid the bone age assessment process.

Data security becomes more and more important in telemammography which uses a public high-speed wide area network connecting the examination site with the mammography expert center. Generally, security is characterized in terms of privacy, authenticity and integrity of digital data. Privacy is a network access issue and is not considered in this paper. We present a method, authenticity and integrity of digital mammography, here which can meet the requirements of authenticity and integrity for mammography image (IM) transmission. The authenticity and integrity for mammography (AIDM) consists of the following four modules. 1) Image preprocessing: To segment breast pixels from background and extract patient information from digitalimaging and communication in medicine (DICOM) image header. 2) Image hashing: To compute an image hash value of the mammogram using the MD5 hash algorithm. 3) Data encryption: To produce a digital envelope containing the encrypted image hash value (digital signature) and corresponding patient information. 4) Data embedding: To embed the digital envelope into the image. This is done by replacing the least significant bit of a random pixel of the mammogram by one bit of the digital envelope bit stream and repeating for all bits in the bit stream. Experiments with digital IMs demonstrate the following. 1) In the expert center, only the user who knows the private key can open the digital envelope and read the patient information data and the digital signature of the mammogram transmitted from the examination site. 2) Data integrity can be verified by matching the image hash value decrypted from the digital signature with that computed from the transmitted image. 3) No visual quality degradation is detected in the embedded image compared with the original. Our preliminary results demonstrate that AIDM is an effective method for image authenticity and integrity in telemammography application.

Chest radiography is one of the most widely used techniques in diagnostic imaging. It makes up at least one third of all conventional diagnostic radiographic procedures in hospitals. However, in both film-screen and computed radiography, images are often digitized with the view and orientation unknown or mislabeled, which causes inefficiency in displaying them in the picture archive and communication system (PACS). Hence, the goal of this work is to provide a robust, efficient, and automatic hanging protocol for chest radiographs. To achieve it, the method star ts with recognition by extracting a set of distinctive features from chest radiographs. Next, a well-defined probabilistic classifier is used to train and classify the radiographs. Identifying the orientation of the radiographs is performed by an efficient algorithm which locates the neck, heart, and abdomen positions in radiographs. The initial experiment was performed on radiographs collected from daily routine chest exams in hospitals, and it has shown promising results.

1.1 The digital reference images provided in the adjunct to this standard illustrate various types and degrees of discontinuities occurring in thin-wall steel investment castings. Use of this standard for the specification or grading of castings requires procurement of the adjunct digital reference images which illustrate the discontinuity types and severity levels. They are intended to provide the following: 1.1.1 A guide enabling recognition of thin-wall steel casting discontinuities and their differentiation both as to type and degree through digitalradiographic examination. 1.1.2 Example digitalradiographic illustrations of discontinuities and a nomenclature for reference in acceptance standards, specifications and drawings. 1.2 Two illustration categories are covered as follows: 1.2.1 Graded—Six common discontinuity types each illustrated in eight degrees of progressively increasing severity. 1.2.2 Ungraded—Twelve single illustrations of additional discontinuity types and of patterns and imper...

Frontal sinus pattern matching is a useful means of forensic identification. By the use of radiographs forensic scientists have recognized that there are diverse anatomical variations in the structure of the frontal sinus. Radiographs are a diagnostic tool, widely used in dental practices, hospitals and other health disciplines. Most health institutions possess the facility to store radiographs over long periods of time. Frontal sinus pattern matching technique can be applied in cases where ante mortem frontal sinus radiographs are available and dental matching cannot be carried out. Frontal sinus pattern matching technique may also be used to corroborate identifications based on other techniques such as fingerprints, teeth, or circumstantial evidence. The present study was carried out to assess the effectiveness of using the radiographicimage of the frontal sinus for personal identification in studied population group. The results concluded that the appearance of the radiographicimage of the frontal sinus is unique for each individual. On this evidence it is proposed that frontal sinus pattern matching can be used for personal identification when other methods have failed.

Age estimation is routinely undertaken by comparing radiographs of the individual in question to published reference samples of individuals of known age. This study examines the reliability of age estimation utilizing the Greulich and Pyle atlas in relation to both left- and right-hand/wrist radiographs and explores whether reversing right-hand/wrist radiographs, so that they are in the same anatomical orientation as those images used in the atlas affects reliability. A total of 403 left-hand/wrist radiographs and 415 right-hand/wrist radiographs were age assessed using the Greulich and Pyle atlas. Analysis showed that there is no significant loss in reliability when radiographs of the right hand (women R(2) = 0.887 and men R(2) = 0.907) are utilized instead of the left (women R(2) = 0.939 and men R(2) = 0.940) or when they are assessed as mirror images to those printed in the reference atlas (reversed female left hand R(2) = 0.929 and reversed male left hand R(2) = 0.931).

A dosimetric survey in paediatric radiology is currently being carried out, aiming at the assessment of patient dose and image quality for chest, abdomen and pelvis radiographs in some age categories at five hospitals in the Tarragona area. Entrance surface dose measurements were performed using homogeneous PMMA phantoms. Effective doses were assessed through the application of published conversion factors. The range of entrance doses averaged by sites was 75-729 {mu}Gy for pelvis radiographs of children aged 5 months, 813-1600 {mu}Gy for pelvis radiographs of children aged 5 years, 94-250 {mu}Gy for chest radiographs of children aged 5 years and 980-2300 {mu}Gy for abdomen radiographs of children aged 5 years. The reference dose values given in the European Guidelines on Quality Criteria for Diagnostic RadiographicImages in Paediatrics were exceeded at two or more hospitals for all projections. The range of average effective dose for the analysed examinations was 14-245 {mu}Sv. The maximum ratios of effective dose by sites varied between 2.2 and 11 for the analysed projections. By examination type, average values in the range 100 to 245 {mu}Sv were estimated for 5 year pelvis and abdomen examinations. (author)

The pulp tissue was removed from 20 mandibular first molar teeth using 2.5% NaOCl irrigation and hand files. The dried canals were infused with radiopaque contrast medium. Standardized conventional and Digora digitalimages were obtained of each tooth positioned in a dried mandible at 0- and 30-degree horizontal angulations. Three evaluators rated the image clarity of the 0- and 30-degree original, enhanced, three-dimensional, zoom, and reverse digitalimage modes as superior, equal, or inferior to corresponding 0- and 30-degree conventional radiographs. The ratings were compared using the Wilcoxon signed rank test. The original, three-dimensional, zoom, or reverse digitalimages were inferior to the conventional radiographs for clarity of canal anatomy. The enhanced digitalimages were not always inferior to the conventional radiographs and were the only images superior to the original digitalimages. Overall, evaluators rated the image clarity of root canal anatomy on conventional radiographs better than on Digora images. However, factors in the experimental design may have contributed to this result.

Soft copy reading of digitalimages has been practiced commonly in the PACS environment. In this study, we compared liquid-crystal display (LCD) and cathode-ray tube (CRT) monitors for detection of pulmonary nodules and interstitial lung diseases on digital chest radiographs by using receiver operating characteristic (ROC) analysis. Digital chest images with a 1000x1000 matrix size and a 8 bit grayscale were displayed on LCD/CRT monitor with 2M pixels in each observer test. Eight and ten radiologists participated in the observer tests for detection of nodules and interstitial diseases, respectively. In each observer test, radiologists marked their confidence levels for diagnosis of pulmonary nodules or interstitial diseases. The detection performance of radiologists was evaluated by ROC analyses. The average Az values (area under the ROC curve) in detecting pulmonary nodules with LCD and CRT monitors were 0.792 and 0.814, respectively. In addition, the average Az values in detecting interstitial diseases with LCD and CRT monitors were 0.951 and 0.953, respectively. There was no statistically significant difference between LCD and CRT for both detection of pulmonary nodules (P=0.522) and interstitial lung diseases (P=0.869). Therefore, we believe that the LCD monitor instead of the CRT monitor can be used for the diagnosis of pulmonary nodules and interstitial lung diseases in digital chest images.

Background Third molar (M3) agenesis and impaction are associated with evolution, changed dietary habits, and human jaw growth. The aim of the study was to radiographically evaluate the prevalence of M3s agenesis, impacted M3s with different impaction patterns, and the approximation of Inferior Dental Canal (IDC) with impacted mandibular M3s roots among the Sriganganagar population. Methods The study included 700 randomly selected subjects from OPD with an age range of 25–45 years. Digital OPGs were taken for all subjects using Kodak 8000C digital OPG machine. The M3 impaction patterns were evaluated using Winter’s classification. Results The prevalence of subjects with at least one M3 agenesis was found to be 34.1% and with 95% confidence interval was 30.6% to 37.6%. The overall M3s agenesis was 16.8% with more prevalence in the males. The patients with agenesis of one M3, two M3s, three M3s, and four M3s were 14.4%, 11.3%, 3.7% and 4.7%, respectively. M3 agenesis was more in the upper jaw and on the left side. The total impacted M3s were 21.11% with more prevalence in mixed diet subjects. Mesioangular was most common impaction pattern, and notching was most prevalent IDC relationship with impacted mandibular M3s roots. Conclusion This study highlighted the evolutionary increasing M3 agenesis and the importance of diagnostic OPG for seeing the status of M3s in jaws.

Third molar (M3) agenesis and impaction are associated with evolution, changed dietary habits, and human jaw growth. The aim of the study was to radiographically evaluate the prevalence of M3s agenesis, impacted M3s with different impaction patterns, and the approximation of Inferior Dental Canal (IDC) with impacted mandibular M3s roots among the Sriganganagar population. The study included 700 randomly selected subjects from OPD with an age range of 25-45 years. Digital OPGs were taken for all subjects using Kodak 8000C digital OPG machine. The M3 impaction patterns were evaluated using Winter's classification. The prevalence of subjects with at least one M3 agenesis was found to be 34.1% and with 95% confidence interval was 30.6% to 37.6%. The overall M3s agenesis was 16.8% with more prevalence in the males. The patients with agenesis of one M3, two M3s, three M3s, and four M3s were 14.4%, 11.3%, 3.7% and 4.7%, respectively. M3 agenesis was more in the upper jaw and on the left side. The total impacted M3s were 21.11% with more prevalence in mixed diet subjects. Mesioangular was most common impaction pattern, and notching was most prevalent IDC relationship with impacted mandibular M3s roots. This study highlighted the evolutionary increasing M3 agenesis and the importance of diagnostic OPG for seeing the status of M3s in jaws.

Detection of X-ray radiation by digitalradiographic systems (DRS) is realized using multi-element detector arrays of scintillator-photodiode (S-PD) type. Accounting for our experience in development of X-ray introscopy systems, possibilities can be found for improvement of DRS detection efficiency. Namely, a more efficient use of the dynamic range of the analog-to-digit converter by means of instrumental compensation of scatter of detector characteristics and smaller apertures of individual detection channels. However, smaller apertures lead to lower levels of useful signals, and a problem emerges of signal interference over neighboring channels, which is related to optical separation of the scintillation elements. Also, more compact arrangement of electronic components of preamplifiers is achieved. The latter problem is solved by using multi-channel (from 32 to 1024 channels) photoreceiving devices (PRD). PRD has a set of photosensitive elements formed on one crystal, as well as shift registers ensuring preliminary amplification of signals and series connection to one outlet. The work envisages creation of receiving-detecting circuit (RDC) with improved spatial resolution (ISR) with the aim of producing advanced DRS with improved characteristics: density resolution better than 0.9%, and detecting ability allowing detection of θ 0.5 mm steel wire behind 6 mm steel. The work will result in the development of RDC with ISR (800-200 microns). In combination with various ionizing radiation sources and scanning mechanisms this will allow creation of DRS for many tasks of non-destructive testing (NDT) and technical diagnostics (TD), in particular, for check-up of pipelines, objects of oil and gas industries, etc. This work was supported by the Ministry of Education and Science of Ukraine, the U.S. Civilian Research and Development Foundation (CRDF), and by the NATO Science for Peace and Security Program (Project SfP-982823).

The purpose of this study was to assess the current status of image quality and dose in computed radiographicdigital mammography (CRDM) systems. Studies included CRDM systems of various models and manufacturers which dose and image quality comparisons were performed. Due to the recent rise in the use of digitalradiographic systems in Mexico, CRDM systems are rapidly replacing conventional film-screen systems without any regard to quality control or image quality standards. Study was conducted in 65 mammography facilities which use CRDM systems in the Mexico City and surrounding States. The systems were tested as used clinically. This means that the dose and beam qualities were selected using the automatic beam selection and photo-timed features. All systems surveyed generate laser film hardcopies for the radiologist to read on a scope or mammographic high luminance light box. It was found that 51 of CRDM systems presented a variety of image artefacts and non-uniformities arising from inadequate acquisition and processing, as well as from the laser printer itself. Undisciplined alteration of image processing settings by the technologist was found to be a serious prevalent problem in 42 facilities. Only four of them showed an image QC program which is periodically monitored by a medical physicist. The Average Glandular Dose (AGD) in the surveyed systems was estimated to have a mean value of 2.4 mGy. To improve image quality in mammography and make more efficient screening mammographic in early detection of breast cancer is required new legislation.

A 61-year-old woman had an intracranial tumour that was located on the falx. Meningioma was suspected and the tumour rapidly grew over 1 year. It showed nearly equal density with spinal fluid showing almost no enhancement on radiographicimages, like microcystic meningioma. Successful removal of the tumour was achieved. Histopathologically, the tumour was diagnosed as low-grade meningioma. The meningioma had variable sized microcysts and the appearance of solid area was meningothelial meningioma. This is a rare radiographicimage for meningothelial meningioma.

Full Text Available We consider an additive group structure in digitalimages and introduce the commutator in digitalimages. Then we calculate the hypercrossed complex pairings which generates a normal subgroup in dimension 2 and in dimension 3 by using 8-adjacency and 26-adjacency.

This article introduces digitalimaging, an Adobe Photoshop course at Shrewsbury High School in Shrewsbury, Massachusetts. Students are able to earn art credits to graduate by successfully completing the course. Digitalimaging must cover art criteria as well as technical skills. The course begins with tutorials created by the instructor and other…

This article introduces digitalimaging, an Adobe Photoshop course at Shrewsbury High School in Shrewsbury, Massachusetts. Students are able to earn art credits to graduate by successfully completing the course. Digitalimaging must cover art criteria as well as technical skills. The course begins with tutorials created by the instructor and other…

Arguing that the news media are about to adopt digitalimaging systems that will have far-reaching implications for the practice of journalism, this paper discusses how the news media is expected to adopt the new technology and explains why the marriage of journalism and digitalimaging will create ethical issues with respect to photo manipulation…

With the introduction of digital flat-panel detector systems into clinical practice, the still unresolved question of resolution requirements for picture archiving communication system (PACS) workstation monitors has gained new momentum. This contrast detail analysis was thus performed to define the differences in observer performance in the detection of small low-contrast objects on clinical 1K and 2K monitor workstations. Images of the CDRAD 2.0 phantom were acquired at varying exposures on an indirect-type digital flat-panel detector. Three observers evaluated a total of 15 images each with respect to the threshold contrast for each detail size. The numbers of correctly identified objects were determined for all image subsets. No significant difference in the correct detection ratio was detected among the observers; however, the difference between the two types of workstations (1K vs 2K monitors) despite less than 3% was significant at a 95% confidence level. Slight but statistically significant differences exist in the detection of low-contrast nodular details visualized on 1K- and 2K-monitor workstations. Further work is needed to see if this result holds true also for comparison of clinical flat-panel detector images and may, for example, exert an influence on the diagnostic accuracy of chest X-ray readings. (orig.)

Results: The correlation determined between the MP3 stages and cervical vertebrae maturity index (CVMI stages, the peak-wise distribution of the MP3 stages, and the correlation between the MP3 stages and the chronological age were found to be highly significant. Conclusions: Digitalradiograph of the MP3 region is definitely a simple, reliable, cost-effective, and time-saving technique for the assessment of skeletal maturity.

To evaluate the diagnostic accuracy of transcranial radiographs and magnetic resonance imaging (MRI) of the temporomandibular joint (TMJ) in the assessment of osseous changes of the condylar head and articular eminence. Osseous changes of the TMJ were evaluated in forty-three patients. Osseous changes of the condylar head and articular eminence were observed in 41 joints and 64 joints, respectively on transcranial radiographs, and 48 joints and 59 joints, respectively on MRI. The flattening, sclerosis, erosion, and osteophyte formation of the condylar heads were observed in 36.6%, 43.9%, 12.2%, and 7.3%, respectively on transcranial radiographs compared with 35.4%, 20.8%, 37.5%, and 6.3%, respectively on MRI. While, the flattening, sclerosis, and erosion of the articular eminences were observed in 26.6%, 67.2%, and 6.2%, respectively on transcranial radiographs compared with 32.2%, 59.3%, and 8.5%, respectively on MRI. There were no statistical differences between transcranial radiographs and MRI scans in the detection of osseous changes of the TMJ. However, MRI scans were superior to the transcranial radiographs in the detection of erosion of the condylar head (p<0.01).

This study investigated the diagnostic accuracy of digital dental radiograpny for detecting carious lesions on approximal surfaces before and after optimization of the environ- ment, and after joint training on evaluation and review of x-rays. A further aim was to evaluate differences in diagnostic accuracy between general dental practitioners (GDPs) and dental hygienists (DHs). One hundred extracted teeth (premolars and molars) underwent standardized radiography. Eleven participants (seven GDPs and four DHs) evaluated digitalimages for approximal carious lesions in three sessions: (1) at current conditions with no optimization or further training, (2) under optimized viewing conditions, and (3) under optimized viewing conditions after a short educational session. Receiver operating characteristic curves were,used to evaluate the results. Histological evaluation was made and served as a cri- terion standard for differentiating sound teeth and teeth with carious lesions. Kappa statistics evaluated intra-observer agreement. Diagnostic accuracy in the GDP group differed sig- nificantlyfor all types of carious lesions between the first and third evaluations (p=0.002), and also between the second and third (p=0.015). Diagnostic accuracy also differed significantly for carious lesions into the dentin between the first and third evaluations (p=0.010) and between the second and third (p=0.015). Most of the staff had optimized the environment when evaluating digitalradiographs. A short educational session highlighting the difficulty of caries diagnostics in digital dental radiography can increase diagnostic accuracy. Diagnostic accuracy in the detection of approximal carious lesions on digitalradiographs did not differ between GDPs and DHs.

This article on digital radiography image processing and display is the second of two articles written as part of an intersociety effort to establish image quality standards for digital and computed radiography. The topic of the other paper is digital radiography image acquisition. The articles were developed collaboratively by the ACR, the American Association of Physicists in Medicine, and the Society for Imaging Informatics in Medicine. Increasingly, medical imaging and patient information are being managed using digital data during acquisition, transmission, storage, display, interpretation, and consultation. The management of data during each of these operations may have an impact on the quality of patient care. These articles describe what is known to improve image quality for digital and computed radiography and to make recommendations on optimal acquisition, processing, and display. The practice of digital radiography is a rapidly evolving technology that will require timely revision of any guidelines and standards.

Signals from defective picture elements rejected. Image processing program for use with charge-coupled device (CCD) or other mosaic imager augmented with algorithm that compensates for common type of electronic defect. Algorithm prevents false interpretation of "hotspots". Used for robotics, image enhancement, image analysis and digital television.

This paper presents the key post-processing algorithms for CR images used in our second generation PACS and its software implementation based on the algorithm features, fault tolerance and multilevel adaptive control, which can enable the benefits of image processing, good performance, speed and reliability.

In the recent years, we have been witnessing a very dynamic development of diagnostic methods of imaging. In contemporary radiology, the carrier of the diagnostic information is the image, obtained as a result of an X-ray beam transmitted through the patient's body, with modulation of intensity, and processing of data collected by the detector. Depending on the diagnostic method used, signals can be detected with analog (x-ray film) or digital systems (CR, DR and DDR). Each of these methods of image acquisition, due to its own technological solutions, determines a different quality of imaging (diagnostic data). The introduction of digitalimage receptors, instead of conventional SF systems, increased the patient dose, as a result of a gradually increasing exposure. This followed from the fact that in digital systems, the increased radiation dose reduces image noise and improves image quality, and that is owing to the data capacity of these systems (impossible in SF systems with a limited data capacity of the image detector). The availability of the multitude of imaging systems, each characterized by disparate qualitative and quantitative parameters, implies the problem of evaluation and enforcement of a proper efficiency from manufacturers of these systems.At the same time, there is a legal problem present in our country, i.e. the lack of laws and regulations regarding standards of the scope of quality control (parameters) and measurement methodology for the systems of digitalimage acquisition. In the European countries, the scope and standards of control are regulated by the manufacturers and European Guidelines, whereas in the United States, AAPM Reports have been introduced, that specifically describe methods of tests performance, their frequency, as well as target values and limits. This paper is a review of both, the scope of quality control parameters of image detectors in analog and digital systems of imaging, and the measurement methodology. The parameters

Full Text Available This paper proposes a basic scheme for understanding the fundamentals of digitalimage processing and the image denising algorithm. There are three basic operation categorized on during image processing i.e. image rectification and restoration, enhancement and information extraction. Image denoising is the basic problem in digitalimage processing. The main task is to make the image free from Noise. Salt & pepper (Impulse noise and the additive white Gaussian noise and blurredness are the types of noise that occur during transmission and capturing. For denoising the image there are some algorithms which denoise the image.

Full Text Available This paper proposes a basic scheme for understanding the fundamentals of digitalimage processing and the image denising algorithm. There are three basic operation categorized on during image processing i.e. image rectification and restoration, enhancement and information extraction. Image denoising is the basic problem in digitalimage processing. The main task is to make the image free from Noise. Salt & pepper (Impulse noise and the additive white Gaussian noise and blurredness are the types of noise that occur during transmission and capturing. For denoising the image there are some algorithms which denoise the image.

Ameloblastic fibroma (AF) is a benign tumor of mixed odontogenic origin, which affects predominantly young individuals. AF appearing as a mixed radiographicimage is very rare. This report describes a case of AF in a 12-year-old male identified during a routine radiographic exam for orthodontic treatment planning. The panoramic radiography revealed a well-defined multilocular mixed image located in the mandible between the roots of the left mandibular second premolar and first molar. The lesion was excised under local anesthesia. Histopathological analysis revealed islands of epithelial cells and columnar peripheral cells showing a nucleus in inverted polarization, interspersed with spindle-shaped cells and abundant extracellular matrix deposition. No atypia was observed. The diagnosis of AF was established. No tumor recurred up to 30 months after treatment. Although rare, AF should be also considered in the differential diagnosis of mixed radiographicimages of the jaws in young patients. Key words:Ameloblastic fibroma, differential diagnosis, incidental finding, mixed image, radiographic features.

Earlier works have shown the feasibility to correct the deformation of the attenuation map in radiographs acquired with conical radiation beams provided that the inspected object could be expressed into analytical geometry terms. This correction reduces the contribution of the main object in the radiograph, allowing thus the visualization of its otherwise concealed heterogeneities. However, the non-punctual character of the source demanded a cumbersome trial-and-error approach in order to determine the proper correction parameters for the algorithm. Within this frame, this work addresses the improvement of radiographs of specially tailored test-objects acquired with a conical beam through correction of its divergence by using the information contained in the image itself. The corrected images have afterwards undergone a filtration in the frequency domain aiming at the reduction of statistical fluctuation and noise by using a 2D Fourier transform. All radiographs have been acquired using 165Dy and 198Au gamma-ray sources produced at the Argonauta research reactor in Institutode Engenharia Nuclear - CNEN, and an X-ray sensitive imaging plate as detector. The processed images exhibit features otherwise invisible in the original ones. Their processing by conventional histogram equalization carried out for comparison purposes did not succeed to detect those features.

In this paper, we introduce a new multiresolution watermarking method for digitalimages. The method is based on the discrete wavelet transform (DWT). Pseudo-random codes are added to the large coefficients at the high and middle frequency bands of the DWT of an image. It is shown that this method is more robust to proposed methods to some common image distortions, such as the wavelet transform based image compression, image rescaling/stretching and image halftoning. Moreover, the method is hierarchical.

Background: The impaction rate is higher for the third molars than for any other tooth in modern human population. This study was conducted with the aim to evaluate the validity of linear and angular measurements on the digital panoramic radiograph as a reference for early prediction of mandibular third molar eruption/impaction. Materials and Methods: Digital panoramic radiographs of 200 subjects were selected based on their status of eruption of mandibular third molars; fully erupted (Group ...

The radiographs play an important role in the diagnosis and management of periodontal disease although the most appropriate form of assessment vary. The great technologic advance and the easily accessible systems of digitalimage analyses, specify digitizedradiographs, improve the diagnostic power. The studied group was 29 adults (14 female and 15 male) ranging in age from 18 to 45 years. They all had evidence of alveolar bone loss and established periodontitis. They were studied, without treatment, over a six month period with four posterior standardized vertical bite wings radiographs, electronic probing of attachment loss, and bacteriological and temperature analysis of periodontal pocket. The aim of this investigation was to determine the relationship between the loss of radiographic crestal bone height and probing attachment loss in digitizedradiographs and show a standardization method for periodontal radiographs. Radiographic and probing attachment change at all sites, dichotomously classified as to not changing or loosing indicated 20.42% of sites were loosing by measurement of radiographic change and 5.29% were loosing by measurement of attachment change. There was concordance between the presence or absence of probing attachment loss and bone loss in 72% to 86% depending on the area. The results, admitting methodological limitations, indicate that when these two methods for the assessment of progressive periodontitis were used they represents measure degrees of different features of periodontitis and that the period of periodontal disease activity was detected in the either the soft tissue attachment or bone. (author). 116 refs., 17 figs., 8 tabs.

Full Text Available The quantity of thoracic radiographies in the medical field is ever growing. An automated system for segmenting the images would help doctors enormously. Some approaches are knowledge-based; therefore we propose here an ontology for this purpose. Thus it is machine oriented, rather than human-oriented. That is all the structures visible on a thoracic image are described from a technical point of view.

When patients see double with both eyes open, known as "binocular diplopia," this may be a harbinger of underlying life-threatening causes. This article presents pertinent anatomy, critical abnormality, and radiographic features that should be double checked for in diplopia. Key areas requiring a double check using the acronym VISION include Vascular, Infectious and Inflammatory, the Scalp for giant cell arteritis, Sphenoid and Skull base in trauma, Increased intracranial pressure (pseudotumor cerebri), Onset of new headaches or psychosis, and Neoplasm. This article reviews the pertinent abnormalities and radiographicimaging critical to assess in patients with diplopia.

Light interaction with a sample modifies both intensity and phase of the illuminating wave. Any available supports for image recording are only sensitive to intensity, but Denis Gabor [P. Marquet, B. Rappaz, P. Magistretti, et. al. Digital Holography for quantitative phase-contrast imaging, Optics Letters, 30, 5, pp 291-93 (2005)] invented in 1948 a way to encode the phase as an intensity variation: the {sup h}ologram{sup .} Digital Holographic Microscopy (DHM) [D. Gabor, A new microscopic principle, Nature, 1948] implements digitally this powerful hologram. Characterization of various pollen grains and of morphology changes of neurones associated with hypotonic shock demonstrates the potential of DHM for imaging cells.

We present a new analysis tool for cervical flexion-extension radiographs based on machine vision and computerized image processing. The method is based on semiautomatic image segmentation leading to detection of common landmarks such as the spinolaminar (SL) line or contour lines of the implanted anterior cervical plates. The technique allows for visualization of the local curvature of these landmarks during flexion-extension experiments. In addition to changes in the curvature of the SL lin...

Digitalimages are routinely used by the publishing industry, but most diagnostic pathologists are unfamiliar with the technology and its possibilities. This review aims to explain the basic principles of digitalimage acquisition, storage, manipulation and use, and the possibilities provided not only in research, but also in teaching and in routine diagnostic pathology. Images of natural objects are usually expressed digitally as 'bitmaps'--rectilinear arrays of small dots. The size of each dot can vary, but so can its information content in terms, for example, of colour, greyscale or opacity. Various file formats and compression algorithms are available. Video cameras connected to microscopes are familiar to most pathologists; video images can be converted directly to a digital form by a suitably equipped computer. Digital cameras and scanners are alternative acquisition tools of relevance to pathologists. Once acquired, a digitalimage can easily be subjected to the digital equivalent of any conventional darkroom manipulation and modern software allows much more flexibility, to such an extent that a new tool for scientific fraud has been created. For research, image enhancement and analysis is an increasingly powerful and affordable tool. Morphometric measurements are, after many predictions, at last beginning to be part of the toolkit of the diagnostic pathologist. In teaching, the potential to create dramatic yet informative presentations is demonstrated daily by the publishing industry; such methods are readily applicable to the classroom. The combination of digitalimages and the Internet raises many possibilities; for example, instead of seeking one expert diagnostic opinion, one could simultaneously seek the opinion of many, all around the globe. It is inevitable that in the coming years the use of digitalimages will spread from the laboratory to the medical curriculum and to the whole of diagnostic pathology.

Second-year veterinary students are often challenged by concepts in veterinary radiology, including the fundamentals of image quality and generation of differential lists. Four card games were developed to provide veterinary students with a supplemental means of learning about radiographicimage quality and differential diagnoses in urogenital imaging. Students played these games and completed assessments of their subject knowledge before and after playing. The hypothesis was that playing each game would improve students' understanding of the topic area. For each game, students who played the game performed better on the post-test than students who did not play that game (all pgames, students who played each respective game demonstrated significant improvement in scores between the pre-test and the post-test (pgames were both helpful and enjoyable. Educationally focused games can help students learn classroom and laboratory material. However, game design is important, as the game using the most passive learning process also demonstrated the weakest results. In addition, based on participants' comments, the games were very useful in improving student engagement in the learning process. Thus, use of games in the classroom and laboratory setting seems to benefit the learning process.

Full Text Available In this paper are presented some results of implementation of digitalwatermarking methods into image coding based on fractal principles. Thepaper focuses on two possible approaches of embedding digitalwatermarks into fractal code of images - embedding digital watermarksinto parameters for position of similar blocks and coefficients ofblock similarity. Both algorithms were analyzed and verified on grayscale static images.

Some results of image recognition tests are given, in which a testee looks at an image and tell if he/she can recognize a certain figure in it or not. When studying digital halftoning process, it is important to discuss the resolution of the human eye, or eye and brain, from the viewpoint of image recognition.

Examines the intersection of conservation and digitalimaging based on guidelines at the Cornell University (Ithaca, NY) library. Discusses the digitization of artifacts; assessing the condition prior to scanning; scanning considerations, including temperature and humidity, lighting, and security; stable storage of artifacts after scanning; and…

This study was designed in order to optimize the optical densitometry technique in radiographicimages by the setorization of the characteristic curves of the radiographic films. We used 24 radiographs of a stepped aluminium wedge that were taken without rigorous control development and manually revealed. The densitometric values of the steps images and its thickness, for each radiographic, was utilized to generate its particular mathematics expressions that represent its characteristic densitometric curves and then it were used for setorization. The densitometric values were obtained by a Macbeth TD528 densitometer. The study showed an optimization in the representation of the relationship between the optical density of the steps images of the wedge and its correspondent thickness, provided by the setorization, with mean square error around 10{sup -5}. This optimization will allow the use of this methodology in quantitative evaluations of bone mass, by radiographicimages. (author)

During the past 15 yr, digital X-ray radiogrammetry (DXR) has been used to measure metacarpal bone mineral density (BMD). BMD is often measured in existing cohorts where X-ray images were not acquired in accordance with the DXR imaging protocol (DIP). The purpose of the present study was to analyze how deviations from DIP in historical radiographs may affect the reproducibility of DXR-BMD measurements. Cadaver hand phantoms were used to conduct repeat measurements of deviations from DIP with respect to voltage, exposure, lateral displacement, supination, combination of lateral displacement and supination or rotation, extension of the wrist, and edge enhancement. Direct digital radiography (Aristos; Siemens Healthcare, Erlangen, Germany) was used for image acquisition and dxr-online (Sectra, Linköping, Sweden) for DXR-BMD measurements. The influence of the tested deviations from DIP ranged from 0 to 32.5 mg/cm(2) (0-6.8%). On repetition with the same specimen, none of the deviations resulted in a within-specimen reproducibility error greater than 2 mg/cm(2) (0.4%, equivalent to a T-score of 0.042). Among the tested deviations, all except tube voltage had a magnitude greater than the normal measurement noise for the technique and must therefore be considered when planning a study based on historical images.

Full Text Available DETECHIP® is a molecular sensing array used for identification of a large variety of substances. Previous methodology for the analysis of DETECHIP® used human vision to distinguish color changes induced by the presence of the analyte of interest. This paper describes several analysis techniques using digitalimages of DETECHIP® . Both a digital camera and flatbed desktop photo scanner were used to obtain Jpeg images. Color information within these digitalimages was obtained through the measurement of redgreen-blue (RGB values using software such as GIMP, Photoshop and ImageJ. Several different techniques were used to evaluate these color changes. It was determined that the flatbed scanner produced in the clearest and more reproducible images. Furthermore, codes obtained using a macro written for use within ImageJ showed improved consistency versus pervious methods.

Full Text Available In order to evaluate density, radiographic contrast and dose of radiation exposure, the author analyzed 80 radiographs containing 640 optical density data of the images of a penetrometer, exposed to the radiation beam with combinations between D and E periapical films, aluminum and copper/aluminum filters, and circular or rectangular collimators. The data obtained were analyzed by ANOVA and allowed the following conclusions: 1 aluminum filtration resulted in improved image contrast; 2 the use of group D film and an aluminum filter produced improved image contrast quality; 3 the rectangular collimator contributed to the production of improved contrast and to the reduction of radiation exposure, but did not affect density; 4 the combination of copper/aluminum filter, E group film and rectangular collimation significantly reduced radiation exposure.

In the growing years, indicators of the level of maturational development of the individual provide the best means for evaluating biologic age and the associated timing of skeletal growth. The relative stage of maturity of a child may be determined by comparing the child's hand-wrist radiograph to the known standards of skeletal development. In this study, we assessed various levels of skeletal maturation and also identified the relationship between chronological age (CA) and maturation stage using the hand-wrist radiographs in adolescents of Indian origin. Three hundred and thirty hand-wrist digitalradiographs of individuals aged 8 to 18 years were evaluated for skeletal maturity levels using Fishman's method. The data was analysed using the SPSS software package (version 12, SPSS Inc., Chicago, IL, USA). Regression analysis was performed for calculating bone age of both males and females. Spearman's rank-order correlation coefficients were estimated separately for males and females to assess the relation between CA and maturation level. An association between skeletal maturation indicator stages and CA (r = 0.82) was significant. Interestingly, female subjects were observed to be advanced in skeletal maturity compared to males. Regression equations were derived to calculate bone age in males, females and the whole sample. The results of this study showed significant association between hand-wrist skeletal maturation levels and CA. Digitalradiographic assessment of hand-wrist skeletal maturation can be used as a better choice for predicting average bone age of an individual because of its simplicity, reliability and lesser radiation exposure.

Muchantef, Karl [Perelman School of Medicine at the University of Pennsylvania, Department of Radiology, The Children' s Hospital of Philadelphia, Philadelphia, PA (United States); McGill University, Department of Diagnostic Radiology, Montreal Children' s Hospital, Montreal (Canada); Epelman, Monica [Perelman School of Medicine at the University of Pennsylvania, Department of Radiology, The Children' s Hospital of Philadelphia, Philadelphia, PA (United States); Nemours Children' s Hospital, Department of Radiology, Orlando, FL (United States); Darge, Kassa; Anupindi, Sudha A. [Perelman School of Medicine at the University of Pennsylvania, Department of Radiology, The Children' s Hospital of Philadelphia, Philadelphia, PA (United States); Kirpalani, Haresh [Perelman School of Medicine at the University of Pennsylvania, Division of Neonatology, The Children' s Hospital of Philadelphia, Philadelphia, PA (United States); Laje, Pablo [Perelman School of Medicine at the University of Pennsylvania, Department of Surgery, The Children' s Hospital of Philadelphia, Philadelphia, PA (United States)

2013-11-15

Abdominal radiography is the reference standard in imaging neonates with necrotizing enterocolitis (NEC); however, ultrasound of the abdomen including bowel may be of value in this setting. To correlate sonographic and radiographic findings with patient outcomes in NEC. We reviewed sonographic and radiographic exams, as well as clinical, pathological and laboratory records. Ultrasound images were reviewed for free intraperitoneal gas, peritoneal fluid, pneumatosis intestinalis, portal gas, bowel vascularity, bowel wall thickness and echogenicity, peristalsis and the presence of dilated bowel with anechoic contents. Contemporaneously acquired radiographs were reviewed for intraperitoneal gas, pneumatosis intestinalis, portal gas, the sentinel loop sign and gas pattern. Patients were categorized into two groups based on clinical outcome. Forty-four neonates receiving 55 sonograms were included. Focal fluid collections, echogenic free fluid, increased bowel wall echogenicity and increased bowel wall thickness were statistically significant in predicting an unfavorable outcome. Other features approached significance in predicting poor outcomes: free peritoneal gas, pneumatosis intestinalis, aperistalsis, bowel wall thinning and absent bowel perfusion. Anechoic free peritoneal fluid predicted a good outcome. The sentinel loop sign on radiographs predicted an unfavorable outcome. Abdominal sonography and radiography in patients with NEC can help prognosticate the outcome. (orig.)

Full Text Available We present a new analysis tool for cervical flexion-extension radiographs based on machine vision and computerized image processing. The method is based on semiautomatic image segmentation leading to detection of common landmarks such as the spinolaminar (SL line or contour lines of the implanted anterior cervical plates. The technique allows for visualization of the local curvature of these landmarks during flexion-extension experiments. In addition to changes in the curvature of the SL line, it has been found that the cervical plates also deform during flexion-extension examination. While extension radiographs reveal larger curvature changes in the SL line, flexion radiographs on the other hand tend to generate larger curvature changes in the implanted cervical plates. Furthermore, while some lordosis is always present in the cervical plates by design, it actually decreases during extension and increases during flexion. Possible causes of this unexpected finding are also discussed. The described analysis may lead to a more precise interpretation of flexion-extension radiographs, allowing diagnosis of spinal instability and/or pseudoarthrosis in already seemingly fused spines.

The relation between height of lumbar discs (measured from lateral radiographic views) and disc degeneration (classified from MR images) deserves attention in view of the wide, often parallel or interchanged use of both methods. The time sequence of degenerative signs and decrease of disc height is controversial. To clarify the issue, this cross-sectional study documents the relation between disc degeneration and disc height in a selected cohort. Forty-three subjects were selected at random from a cohort examined for potential disc-related disease caused by long-term lifting and carrying. From each subject a lateral radiographic view of the lumbar spine as well as findings from an MR investigation of (in most cases) levels T12/L1 to L5/S1 were available; thus, n = 237 lumbar discs were available for measurement and classification. Disc height was measured from the radiographic views with a new protocol compensating for image distortion and permitting comparison with normal, age- and gender-appropriate disc height. Degeneration as well as disc height were classified twice from MR images by independent observers in a blinded fashion. Disc degeneration classified from MR images is not related to a measurable disc height loss in the first stage of degeneration, whereas progressive degeneration goes along with progressive loss of disc height, though with considerable interindividual variation. Loss of disc height classified from MR images is on average compatible with loss of disc height measured from radiographs. In individual discs, however, classification of height loss from MR images is imprecise. The first sign of disc degeneration (a moderate loss of nucleus signal) precedes disc height decrease. As degeneration progresses, disc height decreases. Disc height decrease and progress of degeneration, however, appear to be only loosely correlated. (orig.)

Radiologists often compare sequential radiographs to identify areas of pathologic change; however, this process is prone to error, as human anatomy can obscure the regions of change, causing the radiologists to overlook pathology. Temporal subtraction (TS) images can provide enhanced visualization of regions of change in sequential radiographs and allow radiologists to better detect areas of change in radiographs. Not all areas of change shown in TS images, however, are actual pathology. The purpose of this study was to create a computer-aided diagnostic (CAD) system that identifies which regions of change are caused by pathology and which are caused by misregistration of the radiographs used to create the TS image. The dataset used in this study contained 120 images with 74 pathologic regions on 54 images outlined by an experienced radiologist. High and low ("light" and "dark") gray-level candidate regions were extracted from the images using gray-level thresholding. Then, sampling techniques were used to address the class imbalance problem between "true" and "false" candidate regions. Next, the datasets of light candidate regions, dark candidate regions, and the combined set of light and dark candidate regions were used as training and testing data for classifiers by using five-fold cross validation. Of the classifiers tested (support vector machines, discriminant analyses, logistic regression, and k-nearest neighbors), the support vector machine on the combined candidates using synthetic minority oversampling technique (SMOTE) performed best with an area under the receiver operating characteristic curve value of 0.85, a sensitivity of 85%, and a specificity of 84%.

Since the introduction of digital flat panel detectors into clinical routine the discussion on monitor specifications for primary soft copy reading has gained new impetus. Major concerns exist for viewing of tiny opacities such as pulmonary nodules. In this study CDRAD phantom images were acquired on a caesium iodid/amorphous silicon detector at varying exposure levels. Images were read three times by three observers on a clinical 1K and 2K monitor workstation. All typical workstation functions such as magnification and window/level setting were applied during image reading. Correct detection ratios were calculated according to the CDRAD evaluation manual. Observer ratings were highest for high dose exposure and 2K monitor reading. No significant difference was detected in the correct detection ratio of observers. However, the difference between the two types of workstations (1K versus 2K monitors) despite less than 3% was significant at a 95% confidence level. This is in good accordance with recently published clinical studies. However, further clinical work will be needed to strengthen this laboratory based impression. Given these subtle differences in low contrast detail detection on 1K and 2K clinical PACS workstation we should probably rethink the recommendations of various national boards for the use of 2K monitors.

Full Text Available Objectives Aluminum step wedge (ASW equivalent radiodensity (eRD has been used to quantify restorative material's radiodensity. The aim of this study was to evaluate the effects of image acquisition control (IAC of a digital X-ray system on the radiodensity quantification under different exposure time settings. Materials and Methods Three 1-mm thick restorative material samples with various opacities were prepared. Samples were radiographed alongside an ASW using one of three digitalradiographic modes (linear mapping (L, nonlinear mapping (N, and nonlinear mapping and automatic exposure control activated (E under 3 exposure time settings (underexposure, normal-exposure, and overexposure. The ASW eRD of restorative materials, attenuation coefficients and contrasts of ASW, and the correlation coefficient of linear relationship between logarithms of gray-scale value and thicknesses of ASW were compared under 9 conditions. Results The ASW eRD measurements of restorative materials by three digitalradiographic modes were statistically different (p = 0.049 but clinically similar. The relationship between logarithms of background corrected grey scale value and thickness of ASW was highly linear but attenuation coefficients and contrasts varied significantly among 3 radiographic modes. Varying exposure times did not affect ASW eRD significantly. Conclusions Even though different digitalradiographic modes induced large variation on attenuation of coefficient and contrast of ASW, E mode improved diagnostic quality of the image significantly under the under-exposure condition by improving contrasts, while maintaining ASW eRDs of restorative materials similar. Under the condition of this study, underexposure time may be acceptable clinically with digital X-ray system using automatic gain control that reduces radiation exposure for patient.

Full Text Available OBJECTIVES: This study assessed the bone density gain and its relationship with the periodontal clinical parameters in a case series of a regenerative therapy procedure. MATERIAL AND METHODS: Using a split-mouth study design, 10 pairs of infrabony defects from 15 patients were treated with a pool of bovine bone morphogenetic proteins associated with collagen membrane (test sites or collagen membrane only (control sites. The periodontal healing was clinically and radiographically monitored for six months. Standardized pre-surgical and 6-month postoperative radiographs were digitized for digital subtraction analysis, which showed relative bone density gain in both groups of 0.034 ± 0.423 and 0.105 ± 0.423 in the test and control group, respectively (p>0.05. RESULTS: As regards the area size of bone density change, the influence of the therapy was detected in 2.5 mm² in the test group and 2 mm² in the control group (p>0.05. Additionally, no correlation was observed between the favorable clinical results and the bone density gain measured by digital subtraction radiography (p>0.05. CONCLUSIONS: The findings of this study suggest that the clinical benefit of the regenerative therapy observed did not come with significant bone density gains. Long-term evaluation may lead to a different conclusions.

Reviews the literature relating to the development and application of modern imaging technology between 1987 and 1993. Highlights include image representation, including image data, compression, and image formats; and image access, including indexing and modeling, user interface design, and distributed access. (143 references) (LRW)

In developed countries, clinical manifestation of carious lesions is changing: instead of dentists being confronted with wide-open cavities, more and more hidden caries are seen. For a long time, the focus of the research community was on finding a method for the detection of carious lesions without the need for radiographs. The research on DigitalImaging Fiber-Optic Transillumination (DIFOTI) has been an active domain. The scope of the present article is to describe a novel technology for caries diagnostics based on Near Infrared DigitalImaging Transillumination (NIDIT), and to give first examples of its clinical indications. In addition, the coupling of NIDIT with a head-mounted retinal image display (RID) to improve clinical workflow is presented. The novel NIDIT technology was shown to be useful as a diagnostic tool in several indications, including mainly the detection of proximal caries and, less importantly, for occlusal caries, fissures, and secondary decay around amalgam and composite restorations. The coupling of this technology with a head-mounted retinal image system allows for its very efficient implementation into daily practice.

A new technique, digitalimage velocimetry, is proposed for the measurement of instantaneous velocity fields of time dependent flows. A time sequence of single-exposure images of seed particles are captured with a high-speed camera, and a finite number of the single-exposure images are sampled within a prescribed period in time. The sampled images are then digitized on an image processor, enhanced, and superimposed to construct an image which is equivalent to a multiple exposure image used in both laser speckle velocimetry and particle image velocimetry. The superimposed image and a single-exposure Image are digitally Fourier transformed for extraction of information on the velocity field. A great enhancement of the dynamic range of the velocity measurement is accomplished through the new technique by manipulating the Fourier transform of both the single-exposure image and the superimposed image. Also the direction of the velocity vector is unequivocally determined. With the use of a high-speed video camera, the whole process from image acquisition to velocity determination can be carried out electronically; thus this technique can be developed into a real-time capability.

Full Text Available Synovial sarcoma is the fourth most common type of sarcoma. It represents between 5% -10% of all soft tissue sarcomas and most prevalent in aged between 15 - 40 years. Synovial sarcoma is the most commonly misdiagnosed soft tissue malignancy, initially as an inflammation process,often because it may be slow-growing, have a benign appearance on imaging studies, may vary in size, and may have pain similar to that associated with trauma. A rare case is presented of 17 years old women with a synovial sarcoma biphasic. The primary tumor originated in the left elbow since 2004. Since then, the patient has had repeated passive or active left elbow pain and tenderness. No history of trauma. She has not developed metastases of the lung. The patient refused to have surgery and others medical procedures that already planned and explained to her. The conclusion of this case report point that radiology is important to diagnosis and planning for further management

Full Text Available Age is one of the essential factors in establishing the identity of the person. Estimation of the human age is a procedure adopted by anthropologists, archeologists, and forensic scientists. Inspection of radiographs and subsequent comparison with radiographicimages, in charts yield ′maturity scores′ that help us to assess the age of an individual. Alternative approaches based on digitalization of panoramic radiographs and their computerized storage have recently become available that exploit image analysis to obtain nondestructive metric measurements of both pulp chambers and teeth, which can be used to assess the age of an individual. The purpose of the present study was to present a method for assessing the chronological age based on the relationship between age and measurement of the pulp/tooth area ratio on single-rooted teeth, using orthopantomographs and a computer-aided drafting program AutoCAD 2000.

The digital networks designed specifically for the X-ray departments in the hospitals already were found in open development at beginning the 80's decade. Actually the digital network will be present include the image generation without the necessity to use film in direct form and in its case to print it through a laser ray printers network, an electronic image file, the possibility to integrate the hospitable information system to the electronic expedient which will allow communicate radiograph electronic files and consult by satellite via the problem cases. (Author)

Chest radiographs of 46 patients who had undergone heart transplantation were reviewed with special attention to abnormalities of the cardiac contours. MR imaging in 3 such patients revealed 3 types of double right cardiac contours: the recipient right atrium combined with the donor right atrium; the donor right atrium combined with the recipient left atrium; and a cardiac fat pad combined with the right atrium. A prominent main pulmonary artery was shown by MR imaging to result from leftward displacement of the main pulmonary artery caused by clockwise rotation and transverse position of the transplanted heart. Recognition of these unique radiographic appearances is of value in assessing transplanted hearts and in avoiding misdiagnosis. (orig.).

Pacemakers and implantable cardioverter defibrillators (ICDs) are being increasingly employed in patients suffering from cardiac rhythm disturbances. The principal objective of this article is to familiarize radiologists with pacemakers and ICDs on chest radiographs and CT scans. Therefore, the preferred lead positions according to pacemaker types and anatomic variants are introduced in this study. Additionally, the imaging features of incorrect lead positions and defects, as well as complications subsequent to pacemaker implantation are demonstrated herein.

Steganography is a method of hiding information in other information of different format (container). There are many steganography techniques with various types of container. In the Internet, digitalimages are the most popular and frequently used containers. We consider main image steganography techniques and their advantages and disadvantages. We also identify the requirements of a good steganography algorithm and compare various such algorithms.

With the introduction of photography and photomechanical printing processes in the 19th century, the first age of machine pictures and reproductions emerged. The 20th century introduced computer image processing systems, creating a digitalimaging revolution. Rather than concentrating on the adversarial aspects of the computer's influence on…

Examines various types of private industry optical disk installations in terms of business requirements for digitalimage systems in five areas: records management; transaction processing; engineering/manufacturing; information distribution; and office automation. Approaches for implementing image systems are addressed as well as key success…

Full Text Available The logical way to learn from the architectural space and then be able to design and represent it is, undoubtedly, that of experiencing it through all the sensitive channels that the space wakes up us. But since the last 30 years, much of our learning about space comes from images of architecture and not from the space itself. The art of architecture is drifting towards a visual art and moving away from its existential side. In digitalimages that have flooded the architectural media, digital photographs of existing spaces intermingle with non-existent space renderings (photographs with a virtual camera. The first ones represent existing places but can be altered to change the perception that the observer of the image will have, the second ones speak to us about places that do not exist yet but they present reality portions through extracts from digital photography (textures, trees, people... that compose the image.

The organs of extremity, chest, skull and lumbar were physically simulated using uniform PMMA slabs with different thicknesses alone and using these slabs together with aluminum plates and air gaps (ANSI Phantoms). The variation of entrance surface air kerma and scatter fraction with X-ray beam qualities was investigated for these phantoms and the results were compared with those measured from anthropomorphic phantoms. A flat panel digitalradiographic system was used for all the experiments. Considerable variations of entrance surface air kermas were found for the same organs of different designs, and highest doses were measured for the PMMA slabs. A low contrast test tool and a contrast detail test object (CDRAD) were used together with each organ simulation of PMMA slabs and ANSI phantoms in order to test the clinical image qualities. Digitalimages of these phantom combinations and anthropomorphic phantoms were acquired in raw and clinically processed formats. Variation of image quality with kVp and post processing was evaluated using the numerical metrics of these test tools and measured contrast values from the anthropomorphic phantoms. Our results indicated that design of some phantoms may not be efficient enough to reveal the expected performance of the post processing algorithms.

The organs of extremity, chest, skull and lumbar were physically simulated using uniform PMMA slabs with different thicknesses alone and using these slabs together with aluminum plates and air gaps (ANSI Phantoms). The variation of entrance surface air kerma and scatter fraction with X-ray beam qualities was investigated for these phantoms and the results were compared with those measured from anthropomorphic phantoms. A flat panel digitalradiographic system was used for all the experiments. Considerable variations of entrance surface air kermas were found for the same organs of different designs, and highest doses were measured for the PMMA slabs. A low contrast test tool and a contrast detail test object (CDRAD) were used together with each organ simulation of PMMA slabs and ANSI phantoms in order to test the clinical image qualities. Digitalimages of these phantom combinations and anthropomorphic phantoms were acquired in raw and clinically processed formats. Variation of image quality with kVp and post processing was evaluated using the numerical metrics of these test tools and measured contrast values from the anthropomorphic phantoms. Our results indicated that design of some phantoms may not be efficient enough to reveal the expected performance of the post processing algorithms.

Introduction Replacement of conventional LASER films with digital paper prints as supplement to radiology reports may serve as an economical and environment friendly method. However, it is essential that such a change does not compromise patient’s intended diagnostic outcome. Aim The aim of this study was to assess the reliability and acceptability of digital paper prints for the radiographicimages by the treating physicians and radiologists. Materials and Methods This observational analytical study was done at a tertiary care hospital of New Delhi, India. A total of 58 consecutively ordered wrist radiographs of paediatric patients (6 months to 12 years of age) for ruling out rickets were retrieved from the PACS (Picture Archiving and Communication System). These 58 radiographs, out of which 21 (36.2%) had radiological evidence of rickets over PACS were printed on two different media i.e., LASER films and glossy photographic paper. An objective scoring for the severity of rickets was done on both LASER films and paper prints by six observers independently. Overall comfort level with paper prints was rated on a 1-5 point Likert scale. Data was analysed using STATA 14.0 (Stata Corp, College Station, TX). Results Intra-observer percentage agreement and value of Cohen’s kappa for PACS vs. LASER films and PACS vs. paper prints was equal i.e., 98.3% and 0.97, respectively. Intra-observer agreement between LASER films and paper prints for all six observers was excellent, ranging from 0.92 to 1.00; percentage agreement ranging from 94.8% to 100%. Fracture of ulna/radius present in 4 sets of the X-rays was well demonstrated in both LASER films and paper prints. Comfort level with paper prints was rated as 5 out of 5 by all due to no requirement of any special illuminated view box and dark room. Conclusion This study concludes that the use of paper prints may serve as a reliable alternative to LASER films to communicate the report of wrist radiographs for the treating

This study is designed to compare and evaluate the diagnostic image quality of dental panoramic radiography between conventional and digital systems. Fifty-four panoramic images were collected and divided into three groups consisting of conventional, digital with and without post processing image. Each image was printed out and scored subjectively by two experienced dentists who were blinded to the exposure parameters and system protocols. The evaluation covers of anatomical coverage and structures, density and image contrast. The overall image quality score revealed that digital panoramic with post-processing scored the highest of 3.45±0.19, followed by digital panoramic system without post-processing and conventional panoramic system with corresponding scores of 3.33±0.33 and 2.06±0.40. In conclusion, images produced by digital panoramic system are better in diagnostic image quality than that from conventional panoramic system. Digital post-processing visualization can improve diagnostic quality significantly in terms of radiographic density and contrast.

A new method is proposed for assessing the severity of hip osteoarthritis (OA) based on radiographic hip joint space (HJS) morphology. 64 hips of patients with verified unilateral OA or bilateral OA were studied by digitizing the corresponding pelvic radiographs. Radiographic OA severity was assessed employing the Kellgren and Lawrence (KL) scale. Using custom-developed software, radiographs were enhanced, the margins of both HJSs were outlined, and 64 regions of interest (ROIs), corresponding to the delineated HJSs, were obtained. Employing custom-developed algorithms, an index ("joint space morphological index" - JSMI) evaluating alterations in the shape and size of HJS was introduced, calculated and normalized with respect to each patient's individual anatomy. The JSMI values were used to introduce classification rules concerning the characterization of a hip in accordance with the KL scale. For each patient in the unilateral OA group, the OA severity was expressed as the percentage of the HJS area difference between the patient's osteoarthritic and contralateral normal hip. The per cent HJS area difference and the JSMI values were used in the design of a regression model for providing a quantitative estimation of OA severity. The per cent HJS area difference correlated highly with the pathological JSMI values (r = -0.83, p0.05), and to be strongly correlated with (r = 0.96, p<0.001), the corresponding ones obtained by the computerized approach. Additionally, the implementation of classification rules based on JSMI simplified resulted in classification accuracies identical to the corresponding ones obtained for the JSMI-based rules. The proposed method may be utilized for evaluating OA and monitoring OA progression.

A method of improving a digitalimage is provided. The image is initially represented by digital data indexed to represent positions on a display. The digital data is indicative of an intensity value I.sub.i (x,y) for each position (x,y) in each i-th spectral band. The intensity value for each position in each i-th spectral band is adjusted to generate an adjusted intensity value for each position in each i-th spectral band in accordance with ##EQU1## where S is the number of unique spectral bands included in said digital data, W.sub.n is a weighting factor and * denotes the convolution operator. Each surround function F.sub.n (x,y) is uniquely scaled to improve an aspect of the digitalimage, e.g., dynamic range compression, color constancy, and lightness rendition. The adjusted intensity value for each position in each i-th spectral band is filtered with a common function and then presented to a display device. For color images, a novel color restoration step is added to give the image true-to-life color that closely matches human observation.

A web-based virtual library of peer-reviewed radiological images was created for use in education and clinical decision support. Images were obtained from open-access content of five online radiology journals and one e-learning web site. Figure captions were indexed by Medical Subject Heading (MeSH) codes, imaging modality, and patient age and sex. This digital library provides a new, valuable online resource.

Visual perception is a complex process requiring interaction between the receptors in the eye that sense the stimulus and the neural system and the brain that are responsible for communicating and interpreting the sensed visual information. This process involves several physical, neural, and cognitive phenomena whose understanding is essential to design effective and computationally efficient imaging solutions. Building on advances in computer vision, image and video processing, neuroscience, and information engineering, perceptual digitalimaging greatly enhances the capabilities of tradition

Full Text Available Purpose: To evaluate the correlation between sagittal condylar guidance obtained by protrusive interocclusal records and panoramic radiograph tracing methods in human dentulous subjects. Materials and Methods: The sagittal condylar guidance was determined in 75 dentulous subjects by protrusive interocclusal records using Aluwax through a face bow transfer (HANAU™ Spring Bow, Whip Mix Corporation, USA to a semi-adjustable articulator (HANAU™ Wide-Vue Articulator, Whip Mix Corporation, USA. In the same subjects, the sagittal outline of the articular eminence and glenoid fossa was traced in panoramic radiographs. The sagittal condylar path inclination was constructed by joining the heights of curvature in the glenoid fossa and the corresponding articular eminence. This was then related to the constructed Frankfurt′s horizontal plane to determine the radiographic angle of sagittal condylar guidance. Results: A strong positive correlation existed between right and left condylar guidance by the protrusive interocclusal method (P 0.000 and similarly by the radiographic method (P 0.013. The mean difference between the condylar guidance obtained using both methods were 1.97° for the right side and 3.18° for the left side. This difference between the values by the two methods was found to be highly significant for the right (P 0.003 and left side (P 0.000, respectively. The sagittal condylar guidance obtained from both methods showed a significant positive correlation on right (P 0.000 and left side (P 0.015, respectively. Conclusion: Panoramic radiographic tracings of the sagittal condylar path guidance may be made relative to the Frankfurt′s horizontal reference plane and the resulting condylar guidance angles used to set the condylar guide settings of semi-adjustable articulators.

Measures of scapulothoracic motion are dependent on accurate imaging of the scapula and thorax. Advanced radiographic techniques can provide accurate measures of scapular motion, but the limited 3D imaging volume of these techniques often precludes measurement of thorax motion. To overcome this, a thorax coordinate system was defined based on the position of rib pairs and then compared to a conventional sternum/spine-based thorax coordinate system. Alignment of the rib-based coordinate system was dependent on the rib pairs used, with the rib3:rib4 pairing aligned to within 4.4 ± 2.1 deg of the conventional thorax coordinate system.

Understanding the concepts of radiographicimage quality and artifact formation can be difficult for veterinary students. Two educational card games were previously developed to help students learn about factors affecting contrast and blackness as well as radiographic artifacts. Second-year veterinary students played one of the two card games as a part of their normal studies for their veterinary imaging course and later took the radiographic physics quiz normally administered during the course. Performance on quiz questions related to each of the two games was compared between students who played each respective game and those who did not. The hypothesis was that students who played a game would perform better on related questions than those who did not play that game. For the contrast and blackness questions, students who played the associated game as part of their studies performed better than those who only studied by conventional means (mean 4.3 vs. 3.8 out of 5 points, p=.02). However, there was no significant difference in results between groups for artifacts questions (mean 4.7 vs. 4.5 out of 5 points, p=.35). Based on these results, educational game play can have benefits to student learning, but performance may be dependent on specific game objectives and play mechanics.

Purpose: It has been hypothesized that photographs can facilitate the interpretation of the radiographic characteristics of trabecular bone. The reliability of these photographic and radiographic approaches has been determined, as have various agreements between the two approaches and their correlations with biomechanical characteristics. Material and Methods: Fourteen vertebral bodies were obtained at autopsy from 6 women and 8 men aged 22-76 years. Photographs (n=28) and radiographs (n=28) were taken of midsagittal slices from the third lumbar vertebra. The radiographs and photographs were digitized and the geometric properties of the trabecular architecture were then determined with a digitalimages analysis technique. Information on the compressive strength and ash density of the vertebral body was also available. Results: The geometric properties of both radiographs and photographs could be measured with a high degree of reliability (Cronbach`s {alpha}>0.85). Agreement between the radiographic and photographic approaches was mediocre as only the radiographic measurements showed insignificant correlations (p<0.05) with the biomechanical characteristics. We suggest that optical phenomena may result in the significant correlations between the photographs and the biomechanical characteristics. Conclusion: For digitalimage processing, radiography offers a superior description of the architecture of trabecular bone to that offered by photography. (orig.)

Purpose To investigate the influence of sacral slope on the correlation between measurements of lumbar lordosis obtained by standing radiographs and magnetic resonance images in supine position (MRI). Little information is available on the correlation between measurements of lumbar lordosis obtained by radiographic and MR images. Most relevant studies have shown correlations for the thoracic spine, but detailed analyses on the lumbar spine are lacking. Methods MR images and standing lateral radiographs of 63 patients without actual low back pain or radiographic pathologies of the lumbar spine were analyzed. Standing radiographic measurements included the sagittal parameters pelvic incidence (PI) pelvic tilt (PT), and sacral slope (SS); MR images were used to additionally measure lumbar L1-S1 lordosis and single level lordosis. Differences between radiographic and MRI measurements were analyzed and divided into 4 subgroups of different sacral slope according to Roussouly's classification. Results Global lumbar lordosis (L1-S1) was 44.99° (± 10 754) on radiographs and 47.91° (± 9.170) on MRI, yielding a clinically relevant correlation (r = 0.61, p consideration of the Sacral Slope. Fortschr Röntgenstr 2017; 189: 233 - 239.

With the extension of the application domains for laser imaging radar,it is necessary to find a new technical way to obtain high technical performance and adaptive ability.In this paper,A new concept of digital receiver of laser imaging radar system is presented.This digital receiver is defined as a time varying parameter receiver which possesses large dynamics region and time domain filter.The receiver's mode,component structure as well as every function of its processing are described.The results and laboratorial data show the feasibility of digital reception.Also,it can exploit the inherent nature of laser imaging radar to obtain high probability of detection.

The paper discusses the estimation of the degree of atherosclerosis in the human femoral artery through the use of a digitalimage processing system for vascular angiograms. The film digitizer uses an electronic image dissector camera to scan the angiogram and convert the recorded optical density information into a numerical format. Another processing step involves locating the vessel edges from the digitalimage. The computer has been programmed to estimate vessel abnormality through a series of measurements, some derived primarily from the vessel edge information and others from optical density variations within the lumen shadow. These measurements are combined into an atherosclerosis index, which is found in a post-mortem study to correlate well with both visual and chemical estimates of atherosclerotic disease.

In this work a lossless wavelet-fractal image coder is proposed. The process starts by compressing and decompressing the original image using wavelet transformation and fractal coding algorithm. The decompressed image is removed from the original one to obtain a residual image which is coded by using Huffman algorithm. Simulation results show that with the proposed scheme, we achieve an infinite peak signal to noise ratio (PSNR) with higher compression ratio compared to typical lossless method. Moreover, the use of wavelet transform speeds up the fractal compression algorithm by reducing the size of the domain pool. The compression results of several welding radiographicimages using the proposed scheme are evaluated quantitatively and compared with the results of Huffman coding algorithm.

The present work synthesizes the experimental results obtained in the characterization of 64 micro strips crystalline silicon detector designed for experiments in high energies physics, with the objective of studying its possible application in advanced medical radiography, specifically in digital mammography and angiography. The research includes the acquisition of two-dimensional radiography of a mammography phantom using the scanning method, and its comparison with similar images simulated mathematically for different X rays sources. The paper also shows the experimental radiography of two biological samples taken from biopsies of mammas, where it is possible to identify the presence of possible pathological lesions. The results reached in this work point positively toward the effective possibility of satisfactorily introducing those advanced detectors in medical digitalimaging applications. (Author)

Full Text Available The aim of this study was to investigate the agreement between diagnoses of calcified atheroma seen on panoramic radiographs and color Doppler images. Our interest stems from the fact that panoramic images can show the presence of atheroma regardless of the level of obstruction detected by color Doppler images. Panoramic and color Doppler images of 16 patients obtained from the archives of the Health Department of the city of Valença, RJ, Brazil, were analyzed in this study. Both sides of each patient were observed on the images, with a total of 32 analyzed cervical regions. The level of agreement between diagnoses was analyzed using the Kappa statistics. There was a high level of agreement, with a Kappa value of 0.78. In conclusion, panoramic radiographs can help detecting calcifications in the cervical region of patients susceptible to vascular diseases predisposing to myocardial infarction and cerebrovascular accidents. If properly trained and informed, dentists can refer their patients to a physician for a cardiovascular evaluation in order to receive proper and timely medical treatment.

Background: Although magnetic resonance imaging (MRI) is now considered the gold standard in second-line imaging of patients with suspected scaphoid fracture and negative radiographs, bone scintigraphy can be used in patients with pacemakers, metallic implants, or other contraindications to MRI. Bone scintigraphy is highly sensitive for the detection of fractures, but exact localization of scintigraphic lesions may be difficult and can negatively affect diagnostic accuracy. Purpose: To investigate the influence of image fusion of planar bone scintigraphy and radiographs on image interpretation in patients with suspected scaphoid fracture. Material and Methods: In 24 consecutive patients with suspected scaphoid fracture, a standard planar bone scintigraphy of both hands was supplemented with fusion imaging of the injured wrist. Standard and fusion images were evaluated independently by three experienced nuclear medicine physicians. In addition to the diagnosis, the degree of diagnostic confidence was scored in each case. Results: The addition of fusion images changed the interpretation of each of the three observers in seven, four, and two cases, respectively, reducing the number of positive interpretations of two of the observers from 11 and nine cases to six and seven cases, respectively. The degree of diagnostic confidence increased significantly in two observers, and interobserver agreement increased in all three pairs of observers from 0.83, 0.57, and 0.73 to 0.89, 0.8, and 0.9, respectively. Conclusion: Image fusion of planar bone scintigrams and radiographs has a significant influence on image interpretation and increases both diagnostic confidence and interobserver agreement

Image forensics is a form of image analysis for finding out the condition of an image in the complete absence of any digital watermark or signature.It can be used to authenticate digitalimages and identify their sources.While the technology of exemplar-based inpainting provides an approach to remove objects from an image and play visual tricks.In this paper,as a first attempt,a method based on zero-connectivity feature and fuzzy membership is proposed to discriminate natural images from inpainted images.Firstly,zero-connectivity labeling is applied on block pairs to yield matching degree feature of all blocks in the region of suspicious,then the fuzzy memberships are computed and the tampered regions are identified by a cut set.Experimental results demonstrate the effectiveness of our method in detecting inpainted images.

Full Text Available A natural-image-based VSS scheme (NVSS scheme that shares secret images. A natural-imagebasedsecret image sharing scheme (NSISS that can share a color secret image over n - 1 arbitrary naturalimages and one noise-like share image. Instead of altering the contents of the natural images, the encryptionprocess extracts feature images from each natural image. In order to protect the secret image from transmissionphase. (n, n - NVSS scheme shared secret image over n-1 natural share. The natural shares will be digital imageand printed image. By extracting the features of natural shares we can prepare noise-like share. After thatencryption carried out with noise-like share and secret image. Propose possible ways to hide the noise like shareto reduce the transmission risk problem for the share. In this paper Initially Feature Extraction process has beenperformed for Natural Shares. Here Digitalimage and Printed image have been used as Natural Shares. Withthat extracted features secret image will be encrypted by (n, n - NVSS scheme where process carried by (n-1natural shares. This Encrypted result will be hided using Share-Hiding Algorithm where generated the QR code.In the Recovering of the secret image will be done by Share Extraction Algorithm and also decryptionalgorithm. Finally the secret image with all pixels has been obtained. This proposed possible ways to hide thenoise like share to reduce the transmission risk problem for the share.

Single image super-resolution (SR) method can generate a high-resolution (HR) image from a low-resolution (LR) image by enhancing image resolution. In medical imaging, HR images are expected to have a potential to provide a more accurate diagnosis with the practical application of HR displays. In recent years, the super-resolution convolutional neural network (SRCNN), which is one of the state-of-the-art deep learning based SR methods, has proposed in computer vision. In this study, we applied and evaluated the SRCNN scheme to improve the image quality of magnified images in chest radiographs. For evaluation, a total of 247 chest X-rays were sampled from the JSRT database. The 247 chest X-rays were divided into 93 training cases with non-nodules and 152 test cases with lung nodules. The SRCNN was trained using the training dataset. With the trained SRCNN, the HR image was reconstructed from the LR one. We compared the image quality of the SRCNN and conventional image interpolation methods, nearest neighbor, bilinear and bicubic interpolations. For quantitative evaluation, we measured two image quality metrics, peak signal-to-noise ratio (PSNR) and structural similarity (SSIM). In the SRCNN scheme, PSNR and SSIM were significantly higher than those of three interpolation methods (pmethods without any obvious artifacts. These preliminary results indicate that the SRCNN scheme significantly outperforms conventional interpolation algorithms for enhancing image resolution and that the use of the SRCNN can yield substantial improvement of the image quality of magnified images in chest radiographs.

1.1 These digital reference images illustrate the types and degrees of discontinuities that may be found in aluminum-alloy castings. The castings illustrated are in thicknesses of 1/ 4 in. [6.35 mm] and 3/4 in. [19.1mm]. 1.2 All areas of this standard may be open to agreement between the cognizant engineering organization and the supplier, or specific direction from the cognizant engineering organization. These items should be addressed in the purchase order or the contract. 1.3 The values stated in inch-pound units are to be regarded as standard. 1.4 These digital reference images are not intended to illustrate the types and degrees of discontinuities found in aluminum-alloy castings when performing film radiography. If performing film radiography of aluminum-alloy castings, refer to Reference Radiographs E 155. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and he...

To demonstrate and determine the frequency and location of calcification within cadaveric knees with or without calcification typical of calcium pyrophosphate dihydrate (CPPD), utilizing histologic, radiographic and MR imaging techniques. Ten cadaveric knees of elderly individuals that demonstrated no radiographic evidence of prior surgery or trauma were studied with MR imaging and subsequently sectioned in planes corresponding to those obtained with MR imaging. The slices were imaged with high-resolution radiography. Two musculoskeletal radiologists correlated the anatomic, MR and radiographic findings. Three of the knees, which did not demonstrate calcifications, were utilized as controls. Histologic sections were obtained from four knees that contained calcifications and from the three controls, and analyzed with special histologic stains that demonstrate phosphorus and calcium. Radiographicimaging and histologic analysis demonstrated widespread CPPD crystal deposition in four of the 10 knee specimens (40%). MR imaging demonstrated some calcifications only within the articular cartilage of the femoral condyles in three of the four (75%) specimens that had CPPD deposits. In all four specimens radiographs and histologic analysis were more sensitive than MR imaging. Histologic analysis demonstrated no evidence of CPPD crystals in the control specimens. MR imaging is insensitive to the presence of CPPD deposits in the knee, even when such deposits are widespread. Our study suggests that the sensitivity of MR imaging was significantly better in detecting CPPD deposits in the hyaline cartilage of the femoral condyles when compared with other internal structures, even when such structures contained a higher amount of calcification. (orig.)

is paper proposes a novel elastic model and presents a deformable registration method based on the model.The method registers images without the need to extract reatures from the images,and therefore works directly on grey-level images.A new similarity metric is given on which the formation of external forces is based.The registration method,taking the coarse-to-fine strategy,constructs external forces in larger scales for the first few iterations to rely more on global evidence,and ther in smaller scales for later iterations to allow local refinements.The stiffness of the elastic body decreases as the process proceeds.To make it widely applicable,the method is not restricted to any type of transformation.The variations between images are thought as general free-form deformations.Because the elastic model designed is linearized,it can be solved very efficiently with high accuracy.The method has been successfully tested on MRI images.It will certainly find other uses such as matching time-varying sequences of pictures for motion analysis,fitting templates into images for non-rigid object recognition,matching stereo images for shape recovery,etc.

To investigate the influence of sacral slope on the correlation between measurements of lumbar lordosis obtained by standing radiographs and magnetic resonance images in supine position (MRI). Little information is available on the correlation between measurements of lumbar lordosis obtained by radiographic and MR images. Most relevant studies have shown correlations for the thoracic spine, but detailed analyses on the lumbar spine are lacking. MR images and standing lateral radiographs of 63 patients without actual low back pain or radiographic pathologies of the lumbar spine were analyzed. Standing radiographic measurements included the sagittal parameters pelvic incidence (PI) pelvic tilt (PT), and sacral slope (SS); MR images were used to additionally measure lumbar L1-S1 lordosis and single level lordosis. Differences between radiographic and MRI measurements were analyzed and divided into 4 subgroups of different sacral slope according to Roussouly's classification. Global lumbar lordosis (L1-S1) was 44.99 (± 10754) on radiographs and 47.91 (±9.170) on MRI, yielding a clinically relevant correlation (r = 0.61, p < 0.01). Measurements of single level lordosis only showed minor differences. At all levels except for L5 / S1, lordosis measured by means of standing radiographs was higher than that measured by MRI. The difference in global lumbar L1-S1 lordosis was -2.9 . Analysis of the Roussouly groups showed the largest difference for L1-S1 (-8.3 ) in group 2. In group 4, when measured on MRI, L5 / S1 lordosis (25.71 ) was lower than L4 / L5 lordosis (27.63 ) compared to the other groups. Although measurements of global lumbar lordosis significantly differed between the two scanning technologies, the mean difference was just 2.9 . MRI in supine position may be used for estimating global lumbar lordosis, but single level lordosis should be determined by means of standing radiographs.

This paper proposes a secure approach for encryption and decryption of digitalimages with chaotic map lattices.In the proposed encryption process, eight different types of operations are used to encrypt the pixels of an image and one of them will be used for particular pixels decided by the outcome of the chaotic map lattices. To make the cipher more robust against any attacks, the secret key is modified after encrypting each block of sixteen pixels of the image.The experimental results and security analysis show that the proposed image encryption scheme achieves high security and efficiency.

The field of a digital-image processing has experienced dramatic growth and increasingly widespread applicability in recent years. Fortunately, advances in computer technology have kept pace with the rapid growth in volume of image data in these and other applications. Digitalimage processing has become economical in many fields of research and in industrial and military applications. While each application has requirements unique from the others, all are concerned with faster, cheaper, more accurate, and more extensive computation. The trend is toward real-time and interactive operations, where the user of the system obtains preliminary results within a short enough time that the next decision can be made by the human processor without loss of concentration on the task at hand. An example of this is the obtaining of two-dimensional (2-D) computer-aided tomography (CAT) images. A medical decision might be made while the patient is still under observation rather than days later.

The field of a digital-image processing has experienced dramatic growth and increasingly widespread applicability in recent years. Fortunately, advances in computer technology have kept pace with the rapid growth in volume of image data in these and other applications. Digitalimage processing has become economical in many fields of research and in industrial and military applications. While each application has requirements unique from the others, all are concerned with faster, cheaper, more accurate, and more extensive computation. The trend is toward real-time and interactive operations, where the user of the system obtains preliminary results within a short enough time that the next decision can be made by the human processor without loss of concentration on the task at hand. An example of this is the obtaining of two-dimensional (2-D) computer-aided tomography (CAT) images. A medical decision might be made while the patient is still under observation rather than days later.

Imaging findings in delayed presentation of congenital diaphragmatic hernia can be confusing and misleading, resulting in a delay in diagnosis. To evaluate the often puzzling plain film findings of late-presenting CDH in an effort to determine whether any of the findings could be helpful in arriving at an early diagnosis. We reviewed and documented the plain film findings and clinical data in eight patients seen during the last 20 years with late-presenting CDH. IRB exempt status was obtained in this study. There were five boys and three girls. The age range was 4 months to 12 years with a mean of 2.4 years. Five children presented with acute respiratory problems while three presented with acute abdominal pain. Two children presented with both respiratory and abdominal findings and one also presented with hematemesis. Two children had radiographic findings that were not difficult to analyze while the remaining six had findings that posed initial diagnostic problems. Although not common, late-presenting CDH can result in confusing plain film radiographic findings and a delay in diagnosis. We found that the most important finding in analyzing these radiographs is in evaluating the location and position of the gastric bubble with the more common left-side hernias. (orig.)

DIRS is a digitalimage rectification system for the geometric correction of LANDSAT multispectral scanner digitalimage data. DIRS removes spatial distortions from the data and brings it into conformance with the Universal Transverse Mercator (UTM) map projection. Scene data in the form of landmarks are used to drive the geometric correction algorithms. Two dimensional least squares polynominal and spacecraft attitude modeling techniques for geometric mapping are provided. Entire scenes or selected quadrilaterals may be rectified. Resampling through nearest neighbor or cubic convolution at user designated intervals is available. The output products are in the form of digital tape in band interleaved, single band or CCT format in a rotated UTM projection. The system was designed and implemented on large scale IBM 360 computers.

Full Text Available Steganography is a method of hiding information in other information of different format (container. There are many steganography techniques with various types of container. In the Internet, digitalimages are the most popular and frequently used containers. We consider main image steganography techniques and their advantages and disadvantages. We also identify the requirements of a good steganography algorithm and compare various such algorithms.

The review is presented with particular reference to Skylab S-192 and Landsat MSS imagery. Attention is given to rectification (calibration) processing with emphasis on geometric correction of image distortions. Image enhancement techniques (e.g., the use of high pass digital filters to eliminate gross shading to allow emphasis of the fine detail) are described along with data analysis and system considerations (software philosophy).

The global objective of this cooperation was to lower the cost and improve the quality of breast health care in the United States. We planned to achieve it by designing a very high performance digital radiography unit for breast surgical specimen radiography in the operating room. These technical goals needed to be achieved at reasonable manufacturing costs to enable MedOptics to achieve high market penetration at a profit. Responsibility for overall project execution rested with MedOptics. MedOptics fabricated and demonstrated hardware, and selected components and handled the overall integration. After completion of this CRADA, MedOptics worked with collaborators to demonstrate clinical performance and utility. Finally, the company marketed the device. LLNL convened a multi-directorate expert panel for an intensive review of MedOptics point design. A written brief of panel conclusions and recommendations was prepared. In addition, LLNL was responsible for: computationally simulating the effects of varying so...

This study was performed to examine the effects of image filter on observer performance by counting the number of holes at each wedge step on a radiographicimage. An aluminum step wedge with 11 steps ranged in thickness from 1.5 mm to 16.5 mm in 1.5 mm increments was fabricated for this study. Each step had 10 notched holes with 1.0 mm diameter on the bottom of the step wedge which were ranged in depths from 0.1 mm to 1.0 mm in 0.1 mm increments. Digitalradiographic raw images of the aluminum step wedge were acquired by using CCD intraoral sensor. The images were processed using several types of noise reduction filters and kernel sizes. Three observers counted the number of holes which could be discriminated on each step. The data were analyzed by ANOVA. The number of holes at each step was decreased as the thickness of step was increased. The number of holes at each step on the raw images was significantly higher than that on the processed images. The number of holes was different according to the types and kernel sizes of the image filters. The types and kernel sizes of image filters on observer performance were important, therefore, they should be standardized for commercial digitalimaging systems.

A network of sites for citizen scientists to take a consistent time sequence of digital photographs of the landscape and an Internet site (http://picturepost.unh.edu/) that efficiently stores and distributes the digitalimages creates a low-cost and sustainable resource for scientific environmental monitoring and formal and informal science education. Digital photographs taken from the same location and positioned in the same direction and orientation allow scientists to monitor a variety of environmental parameters, including plant health, growth, and phenology; erosion and deposition; water levels; and cloud and canopy cover. The PicturePost platform is simply an octagon placed in the center of a flat surface and secured to a post anchored in the ground or onto a building. The edges of the octagon allow positioning of the camera so the complete landscape may be photographed in less than a minute. A NASA-funded project, Digital Earth Watch (aka Measuring Vegetation Health, (http://mvh.sr.unh.edu) provides educational activities and background materials that help people learn about plants as environmental “green canaries” and about the basics of cameras and digitalimages. The website also provides free software to analyze digitalimages. Although this project has been in development for four years, it is only beginning to find partners in which the data support multiple efforts. A large part of this integration is a result of recent NASA funding, which has allowed a new website to be developed to archive and display the images. The developing collaborations and the development of the new website at the same time enhanced both efforts. Because the website could include tools/features that appealed to the collaborating groups, all participants contributed ideas facing fewer restrictions. PicturePost made from recycled plastic lumber.

Presently, tree coders are the best bi-level image coders. The currentISO standard, JBIG, is a good example.By organising code length calculations properly a vast number of possible models (trees) can be investigated within reasonable time prior to generating code.A number of general-purpose code...

Most of the foreign bodies detected in adult gastrointestinal systems are accidentally swallowed pins. In this study, we presented a case with intracolonic multiple pebbles. A 20-year-old man was admitted to emergency surgery policlinic for abdominal pain for 2 d without any alleviation or aggravation. His upright plain abdominal radiographicimaging revealed about 30-40 overt dense opacities in lumen of colonic segments, with oval and well shaped contours, each approximately 1cm x 1cm in size. The multiplanar reconstructions and threedimensional images combined with sectional screening showed that all pebbles had passed completely into the colon and no foreign bodies had remained in the ileal segments. On psychiatric assessment, he was found to have immature personality features, difficulty in overcoming stressors and adaptation disorder. He recovered by conservative management and radiographic monitoring applied during his follow-up. Thus, it can be concluded that, in differential diagnosis of abdominal pain in adult ages, though less frequently seen than in children,gastrointestinal system foreign bodies should always be kept in mind and it should be considered that ingestion of pebbles may be one of the factors contributing to abdominal pain particularly in young adults with psychiatric problems. In such cases suspected of having foreign bodies which cannot be detected by plain films, abdominal tomography can be an alternative for diagnostic imaging.

Scoliosis classification is useful for guiding the treatment and testing the clinical outcome. State-of-the-art classification procedures are inherently unreliable and non-reproducible due to technical and human judgmental error. In the current diagnostic system each examiner will have diagrammatic summary of classification procedure, number of scoliosis curves, apex level, etc. It is very difficult to define the required anatomical parameters in the noisy radiographs. The classification system demands automatic image understanding system. The proposed automated classification procedures extracts the anatomical features using image processing and applies classification procedures based on computer assisted algorithms. The reliability and reproducibility of the proposed computerized image understanding system are compared with manual and computer assisted system using Kappa values.

In this research paper, the authors propose a new approach to digitalimage compression using crack coding This method starts with the original image and develop crack codes in a recursive manner, marking the pixels visited earlier and expanding the entropy in four directions. The proposed method is experimented with sample bitmap images and results are tabulated. The method is implemented in uni-processor machine using C language source code.

This study was performed to evaluate the diagnostic efficacy of panoramic radiography and cone-beam computed tomography (CBCT) in detecting sinus pathology. This study was based on a retrospective evaluation of patients who had undergone both a panoramic radiograph and a CBCT exam. A total of 100 maxillary sinuses were evaluated. Four examiners with various levels of expertise evaluated the images using a five-point scoring system. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic efficacy of the two modalities. The image analysis was repeated twice, with at least two weeks between the evaluation sessions. Interobserver reliability was assessed using Cronbach's alpha, and intraobserver reliability was assessed using Cohen's kappa. Maxillary sinus pathology was detected in 72% of the patients. High interobserver and intraobserver reliability were observed for both imaging modalities and among the four examiners. Statistical analyses using ROC curves demonstrated that the CBCT images had a larger area under the curve (0.940) than the panoramic radiographs (0.579). Three-dimensional evaluation of the sinus with CBCT was significantly more reliable in detecting pathology than panoramic imaging.

In this paper, a method to fingerprint digitalimages is proposed, and different watermarked copies with different identification string are made. After determining the number of the customers and the length of the watermark string, this method chooses some values inside the digitalimage using a characteristic function, and adds watermarks to these values in a way that can protect the product against the attacks happened by comparing two fingerprinted copies.The watermarks are a string of binary numbers -1s and 1s. Every customer will be distinguished by a series of 1s and -1s generated by a pseudo-random generator. The owner of the image can determine the number of customers and the length of the string as well as this method will add another watermarking values to watermark string to protect the product.

experienced nuclear medicine physicians. In addition to the diagnosis, the degree of diagnostic confidence was scored in each case. Results: The addition of fusion images changed the interpretation of each of the three observers in seven, four, and two cases, respectively, reducing the number of positive....... Bone scintigraphy is highly sensitive for the detection of fractures, but exact localization of scintigraphic lesions may be difficult and can negatively affect diagnostic accuracy. Purpose: To investigate the influence of image fusion of planar bone scintigraphy and radiographs on image interpretation...... in patients with suspected scaphoid fracture. Material and Methods: In 24 consecutive patients with suspected scaphoid fracture, a standard planar bone scintigraphy of both hands was supplemented with fusion imaging of the injured wrist. Standard and fusion images were evaluated independently by three...

experienced nuclear medicine physicians. In addition to the diagnosis, the degree of diagnostic confidence was scored in each case. RESULTS: The addition of fusion images changed the interpretation of each of the three observers in seven, four, and two cases, respectively, reducing the number of positive....... Bone scintigraphy is highly sensitive for the detection of fractures, but exact localization of scintigraphic lesions may be difficult and can negatively affect diagnostic accuracy. PURPOSE: To investigate the influence of image fusion of planar bone scintigraphy and radiographs on image interpretation...... in patients with suspected scaphoid fracture. MATERIAL AND METHODS: In 24 consecutive patients with suspected scaphoid fracture, a standard planar bone scintigraphy of both hands was supplemented with fusion imaging of the injured wrist. Standard and fusion images were evaluated independently by three...

experienced nuclear medicine physicians. In addition to the diagnosis, the degree of diagnostic confidence was scored in each case. Results: The addition of fusion images changed the interpretation of each of the three observers in seven, four, and two cases, respectively, reducing the number of positive....... Bone scintigraphy is highly sensitive for the detection of fractures, but exact localization of scintigraphic lesions may be difficult and can negatively affect diagnostic accuracy. Purpose: To investigate the influence of image fusion of planar bone scintigraphy and radiographs on image interpretation...... in patients with suspected scaphoid fracture. Material and Methods: In 24 consecutive patients with suspected scaphoid fracture, a standard planar bone scintigraphy of both hands was supplemented with fusion imaging of the injured wrist. Standard and fusion images were evaluated independently by three...

In this paper, a new technique is proposed for rotation, scaling and translation (RST) invariant image watermarking based on log-polar mappings (LPM) and phase-only filtering (POF). The watermark is embedded in the LPM of Fourier magnitude spectrum of the original image, and a small portion of resulting LPM spectrum is used to calculate the watermark positions. This technique avoids computing inverse log-polar mapping (ILPM) to preserve the quality of the watermarked image, and avoids exhaustive search to save computation time and reduce false detection. Experimental results demonstrate that the digital watermarking technique is invariant and robust to rotation, scaling, and translation transformation.

It is described how digitalimage processing is used for measuring the length of fatigue cracks. The system is installed in a Personal Computer equipped with image processing hardware and performs automated measuring on plane metal specimens used in fatigue testing. Normally one can not achieve...... a resolution better then that of the image processing equipment. To overcome this problem an extrapolation technique is used resulting in a better resolution. The system was tested on a specimen loaded with different loads. The error σa was less than 0.031 mm, which is of the same size as human measuring...

It is described how digitalimage processing is used for measuring the length of fatigue cracks. The system is installed in a Personal, Computer equipped with image processing hardware and performs automated measuring on plane metal specimens used in fatigue testing. Normally one can not achieve...... a resolution better than that of the image processing equipment. To overcome this problem an extrapolation technique is used resulting in a better resolution. The system was tested on a specimen loaded with different loads. The error σa was less than 0.031 mm, which is of the same size as human measuring...

Digitalimage compression (reduction of the amount of numeric data needed to represent a picture) is widely used in electronic storage and transmission devices. Few studies have compared the suitability of the different compression algorithms for dermatologic images. We aimed at comparing the performance of four popular compression formats, Tagged Image File (TIF), Portable Network Graphics (PNG), Joint Photographic Expert Group (JPEG), and JPEG2000 on clinical and videomicroscopic dermatologic images. Nineteen (19) clinical and 15 videomicroscopic digitalimages were compressed using JPEG and JPEG2000 at various compression factors and TIF and PNG. TIF and PNG are "lossless" formats (i.e., without alteration of the image), JPEG is "lossy" (the compressed image has a lower quality than the original), JPEG2000 has a lossless and a lossy mode. The quality of the compressed images was assessed subjectively (by three expert reviewers) and quantitatively (by measuring, point by point, the color differences from the original). Lossless JPEG2000 (49% compression) outperformed the other lossless algorithms, PNG and TIF (42% and 31% compression, respectively). Lossy JPEG2000 compression was slightly less efficient than JPEG, but preserved image quality much better, particularly at higher compression factors. For its good quality and compression ratio, JPEG2000 appears to be a good choice for clinical/videomicroscopic dermatologic image compression. Additionally, its diffusion and other features, such as the possibility of embedding metadata in the image file and to encode various parts of an image at different compression levels, make it perfectly suitable for the current needs of dermatology and teledermatology.

Presently, tree coders are the best bi-level image coders. The currentISO standard, JBIG, is a good example.By organising code length calculations properly a vast number of possible models (trees) can be investigated within reasonable time prior to generating code.A number of general-purpose coders...... version that is substantially faster than its precursorsand brings it close to the multi-pass coders in compression performance.Handprinted characters are of unequal complexity; recent work by Singer and Tishby demonstrates that utilizing the physiological process of writing one can synthesize cursive...

A technique for measuring inter-vertebral motion by the digitization and processing of intensifier images is described. The technique reduces the time and X-ray dosage currently required to make such assessments. The errors associated with computing kinematic indices at increments of coronal plane rotations in the lumbar spine have been calculated using a calibration model designed to produce a facsimile of in vivo conditions in terms of image quality and geometric distortion. (author).

Full Text Available Oculodentodigital dysplasia (ODDD, also known as oculodento-osseous dysplasia, is an extremely rare autosomal dominant disorder with high penetrance, intra- and interfamilial phenotypic variability, and advanced paternal age in sporadic cases. The incidence of this disease is not precisely known, with only 243 cases reported in the scientific literature, suggesting an incidence of around 1 in 10 million people. It is marked mainly by eye abnormalities, craniofacial dysmorphism, dental anomalies, hand and foot malformations, various skeletal defects, and mildly delayed mental development. Neurological changes may appear earlier in each subsequent generation. This case report describes a radiological diagnosis of ODDD based on physical appearance, clinical features and radiographic findings in a 16-year-old girl.

The principle of radiodiagnosis consists in the fact the X-ray beam is attenuated at different degrees by distinct tissues. For this reason, the anatomical structures have distinct radiological opacities, that produce the radiographicimage. The progresses in radiology are related to the development if new radiographicimage formation systems that enable an amplification in the quality, with low dose and/or risk to the patient. The objective of this work is the sensitometric valuation of a screen-film combination, that is still the most used, for the standardization, of radiographicimages. Thinking about this, were constructed homogeneous phantoms of the chest, skull and pelvis, for the calibration of X-ray beams, with the purpose of obtaining radiographicimages of good quality, basing in the routine of a radiodiagnosis service and in the scientific knowledge. Questions were approached about the choice of the suitable equipment, that allow the obtention of k Vp and m As combinations, to produce radiographicimages of good quality, and the reproduction of these combinations to any conventional equipment of diagnostic X-rays. Also presented are the comparison of the doses imparted by these combinations and those used in routine of the Hospital das Clinicas da Faculdade de Medicina de Ribeirao Preto`s radiodiagnosis service. (author) 24 refs., 27 figs., 12 tabs.

Introduction One of the most spectacular physiographic images of the conterminous United States, and the first to have been produced digitally, is that by Thelin and Pike (USGS I-2206, 1991). The image is remarkable for its crispness of detail and for the natural appearance of the artificial land surface. Our goal has been to produce a shaded-relief image of Alaska that has the same look and feel as the Thelin and Pike image. The Alaskan image could have been produced at the same scale as its lower 48 counterpart (1:3,500,000). But by insetting the Aleutian Islands into the Gulf of Alaska, we were able to print the Alaska map at a larger scale (1:2,500,000) and about the same physical size as the Thelin and Pike image. Benefits of the 1:2,500,000 scale are (1) greater resolution of topographic features and (2) ease of reference to the U.S. Geological Survey (USGS) (1987) Alaska Map E and the statewide geologic map (Beikman, 1980), which are both 1:2,500,000 scale. Manually drawn, shaded-relief images of Alaska's land surface have long been available (for example, Department of the Interior, 1909; Raisz, 1948). The topography depicted on these early maps is mainly schematic. Maps showing topographic contours were first available for the entire State in 1953 (USGS, 1:250,000) (J.H. Wittmann, USGS, written commun., 1996). The Alaska Map E was initially released in 1954 in both planimetric (revised in 1973 and 1987) and shaded-relief versions (revised in 1973, 1987, and 1996); topography depicted on the shaded-relief version is based on the 1:250,000-scale USGS topographic maps. Alaska Map E was later modified to include hypsometric tinting by Raven Maps and Images (1989, revised 1993) as copyrighted versions. Other shaded-relief images were produced for The National Geographic Magazine (LaGorce, 1956; 1:3,000,000) or drawn by Harrison (1970; 1:7,500,000) for The National Atlas of the United States. Recently, the State of Alaska digitally produced a shaded-relief image

Full Text Available An Image would yield better impact in convincing someone of something rather than pure description by words. Digitalimages are widely used in various fields like medical imaging, journalism, scientific manipulations and digital forensics. However, images are not reliable as it may be. Digitalimages can be easily tampered with image editing tools. One of the major problems in image forensics is determining if a particular image is authentic or not. Digitalimage forensic is an emerging field of image processing area. Copy-move forgery is one type of image forgery in digitalimage forensic where various methods have been proposed in the field to detect the forgery. In this paper a technique is presented to detect Copy-Move Forgery based on SURF and KD-Tree for multidimensional data matching. We demonstrate our method with high resolution images affected by copy-move forgery.

Full Text Available A low-cost airborne digitalimaging system capable to perform aerial surveys with small-format cameras isintroduced. The equipment is intended to obtain high-resolution multispectral digital photographs constituting so aviable alternative to conventional aerial photography and satellite imagery. Monitoring software handles all theprocedures involved in image acquisition, including flight planning, real-time graphics for aircraft position updatingin a mobile map, and supervises the main variables engaged in the imaging process. This software also creates fileswith the geographical position of the central point of every image, and the flight path followed by the aircraftduring the entire survey. The cameras are mounted on a three-axis stabilized platform. A set of inertial sensorsdetermines platform's deviations independently from the aircraft and an automatic control system keeps thecameras at a continuous nadir pointing and heading, with a precision better than ± 1 arc-degree in three-axis. Thecontrol system is also in charge of saving the platform’s orientation angles when the monitoring software triggersthe camera. These external orientation parameters, together with a procedure for camera calibration give theessential elements for image orthocorrection. Orthomosaics are constructed using commercial GIS software.This system demonstrates the feasibility of large area coverage in a practical and economical way using smallformatcameras. Monitoring and automatization reduce the work while increasing the quality and the amount ofuseful images.

automated neutron tomography facility has been built at the Atominstitut with this detector. DigitalImage Processing: Due to special detector properties of the CCD-camera NR detector, a standard image processing procedure has been developed that always has to be applied, when the CCD-detector is used. It consists of the following steps: white spot correction - dark frame correction and flat field correction. Radiation, which hits the CCD-chip causes an overflow of one or several pixels, which appears in the image as white spots. These disturbing spots have to be removed by means of digitalimage processing. Several filters have been tested, but the results were insufficient. Therefore, a new threshold-median-mean value filter was designed and a proper code was written in IDL (interactive data language). The new filter removes white spots very well by hardly blurring the images. A dark frame is an image made with closed camera shutter. It contains undesired detector signal caused by read out noise and dark cu...

Compton scattering and diffuse scattering degenerate the contrast in radiographicimages. To avoid such scattering effects, a grid, between the patient and the film is currently used to improve the image quality. Teaching this topic to medical physics students requires demonstration experiments. In this paper, an optical analog to an x-ray…

Full Text Available Present day application requires various version kinds of images and pictures as sources of information for interpretation and analysis. Whenever an image is converted from one form to another, such as, digitizing, scanning, transmitting, storing, etc. Some form of degradation occurs at the output. Hence, the output image has to undergo a process called image enhancement which consist of a collection of techniques that seeks to improve the visual appearances of an image. Image enhancement technique is basically improving the perception of information in images for human viewers and providing 'better' input for other automated image processing techniques. This thesis presents a new approach for image enhancement with fuzzy interface system. Fuzzy techniques can manage the vagueness and ambiguity efficiently (an image can be represented as fuzzy set. Fuzzy logic is a powerful tool to represent and process human knowledge in form of fuzzy if-then rules. Compared to other filtering techniques, fuzzy filter gives the better performance and is able to represent knowledge in a comprehensible way.

Background: Skull radiographic examination is a potentially useful procedure for the personal identification in cases where fragments of skull persist with no likelihood of identification based on dental arch. Aims: The study was to determine the uniqueness and reliability of combined frontal sinus (FS) and nasal septum (NS) patterns as observed on posterioanterior (PA) cephalograms for personal identification. Materials and Methods: The randomly selected 149 digital PA cephalograms taken on Kodak 8000C Digital Panoramic and Cephalometric system were evaluated for patterns of FS and NS. Also the distribution of lobulations, area, and ratio of height/width of FS was calculated. The data obtained was statistical analyzed using Pearson's coefficient correlation. Results: FS symmetry was observed in 78.5% and asymmetry in 7.3% subjects. Bilateral aplasia was noticed in 5.3% and unilateral aplasia in 8.7% of subjects. The total lobulation of FS was noted more in males on both sides while center lobes were observed slightly more in females. The straight NS was maximally seen followed by reverse sigmoid. The mean ratio of width/height of FS was observed more in males and highly significant correlation was observed with both sexes. The mean area of FS was noted more in males. There was significant correlation found between patterns of NS and FS except in right dominated asymmetrical FS. Conclusion: The combined use of FS and NS patterns could be used as method for identification by exclusion in forensics. PMID:25789248

Full Text Available Background: Skull radiographic examination is a potentially useful procedure for the personal identification in cases where fragments of skull persist with no likelihood of identification based on dental arch. Aims: The study was to determine the uniqueness and reliability of combined frontal sinus (FS and nasal septum (NS patterns as observed on posterioanterior (PA cephalograms for personal identification. Materials and Methods: The randomly selected 149 digital PA cephalograms taken on Kodak 8000C Digital Panoramic and Cephalometric system were evaluated for patterns of FS and NS. Also the distribution of lobulations, area, and ratio of height/width of FS was calculated. The data obtained was statistical analyzed using Pearson′s coefficient correlation. Results: FS symmetry was observed in 78.5% and asymmetry in 7.3% subjects. Bilateral aplasia was noticed in 5.3% and unilateral aplasia in 8.7% of subjects. The total lobulation of FS was noted more in males on both sides while center lobes were observed slightly more in females. The straight NS was maximally seen followed by reverse sigmoid. The mean ratio of width/height of FS was observed more in males and highly significant correlation was observed with both sexes. The mean area of FS was noted more in males. There was significant correlation found between patterns of NS and FS except in right dominated asymmetrical FS. Conclusion: The combined use of FS and NS patterns could be used as method for identification by exclusion in forensics.

An adaptive vector quantizer (VQ) using a clustering technique known as adaptive fuzzy leader clustering (AFLC) that is similar in concept to deterministic annealing for VQ codebook design has been developed. This vector quantizer, AFLC-VQ, has been designed to vector quantize wavelet decomposed sub images with optimal bit allocation. The high- resolution sub images at each level have been statistically analyzed to conform to generalized Gaussian probability distributions by selecting the optimal number of filter taps. The adaptive characteristics of AFLC-VQ result from AFLC, an algorithm that uses self-organizing neural networks with fuzzy membership values of the input samples for upgrading the cluster centroids based on well known optimization criteria. By generating codebooks containing codewords of varying bits, AFLC-VQ is capable of compressing large color/monochrome medical images at extremely low bit rates (0.1 bpp and less) and yet yielding high fidelity reconstructed images. The quality of the reconstructed images formed by AFLC-VQ has been compared with JPEG and EZW, the standard and the well known wavelet based compression technique (using scalar quantization), respectively, in terms of statistical performance criteria as well as visual perception. AFLC-VQ exhibits much better performance than the above techniques. JPEG and EZW were chosen as comparative benchmarks since these have been used in radiographicimage compression. The superior performance of AFLC-VQ over LBG-VQ has been reported in earlier papers.

A framework for radiographicimage segmentation under topological control based on two-dimensional (2D) image analysis was developed. The system is intended for use in common radiological tasks including fracture treatment analysis, osteoarthritis diagnostics and osteotomy management planning. The segmentation framework utilizes a generic three-dimensional (3D) model of the bone of interest to define the anatomical topology. Non-rigid registration is performed between the projected contours of the generic 3D model and extracted edges of the X-ray image to achieve the segmentation. For fractured bones, the segmentation requires an additional step where a region-based active contours curve evolution is performed with a level set Mumford-Shah method to obtain the fracture surface edge. The application of the segmentation framework to analysis of human femur radiographs was evaluated. The proposed system has two major innovations. First, definition of the topological constraints does not require a statistical learning process, so the method is generally applicable to a variety of bony anatomy segmentation problems. Second, the methodology is able to handle both intact and fractured bone segmentation. Testing on clinical X-ray images yielded an average root mean squared distance (between the automatically segmented femur contour and the manual segmented ground truth) of 1.10 mm with a standard deviation of 0.13 mm. The proposed point correspondence estimation algorithm was benchmarked against three state-of-the-art point matching algorithms, demonstrating successful non-rigid registration for the cases of interest. A topologically constrained automatic bone contour segmentation framework was developed and tested, providing robustness to noise, outliers, deformations and occlusions. (orig.)

We have developed a digital histology imaging system that has the potential to improve the accuracy of surgical margin assessment in the treatment of breast cancer by providing finer sampling and 3D visualization. The system is capable of producing a 3D representation of histopathology from an entire lumpectomy specimen. We acquire digital photomicrographs of a stack of large (120 x 170 mm) histology slides cut serially through the entire specimen. The images are then registered and displayed in 2D and 3D. This approach dramatically improves sampling and can improve visualization of tissue structures compared to current, small-format histology. The system consists of a brightfield microscope, adapted with a freeze-frame digital video camera and a large, motorized translation stage. The image of each slide is acquired as a mosaic of adjacent tiles, each tile representing one field-of-view of the microscope, and the mosaic is assembled into a seamless composite image. The assembly is done by a program developed to build image sets at six different levels within a multiresolution pyramid. A database-linked viewing program has been created to efficiently register and display the animated stack of images, which occupies about 80 GB of disk space per lumpectomy at full resolution, on a high-resolution (3840 x 2400 pixels) colour monitor. The scanning or tiling approach to digitization is inherently susceptible to two artefacts which disrupt the composite image, and which impose more stringent requirements on system performance. Although non-uniform illumination across any one isolated tile may not be discernible, the eye readily detects this non-uniformity when the entire assembly of tiles is viewed. The pattern is caused by deficiencies in optical alignment, spectrum of the light source, or camera corrections. The imaging task requires that features as small as 3.2 &mum in extent be seamlessly preserved. However, inadequate accuracy in positioning of the translation

In a first part, the different techniques of digital thoracic radiography are described. Since computed radiography with phosphore plates are the most commercialized it is more emphasized. But the other detectors are also described, as the drum coated with selenium and the direct digital radiography with selenium detectors. The other detectors are also studied in particular indirect flat panels detectors and the system with four high resolution CCD cameras. In a second step the most important image processing are discussed: the gradation curves, the unsharp mask processing, the system MUSICA, the dynamic range compression or reduction, the soustraction with dual energy. In the last part the advantages and the drawbacks of computed thoracic radiography are emphasized. The most important are the almost constant good quality of the pictures and the possibilities of image processing.

Full Text Available Testing the method of speckle pattern processing based on the digitalimage correlation is carried out in the current work. Three the most widely used formulas of the correlation coefficient are tested. To determine the accuracy of the speckle pattern processing, test speckle patterns with known displacement are used. The optimal size of a speckle pattern template used for determination of correlation and corresponding the speckle pattern displacement is also considered in the work.

The advancement of technology in recent years has the production of increasingly sophisticated devices, in order thus to obtain medical images with high technical level and also facilitate the operation of the equipment. The phantoms were created to ensure a more accurate diagnosis with the minimum dose without exposing patients. Also, to obtain data and verify the performance of a radiography system with a view to ensuring the quality control standards. The objective of this paper is to present and validate a methodology for the construction of a phantom for the control of digital quality radiographicimage. (author)

The Internet as a whole does not use secure links, thus information in transit may be vulnerable to interruption as well. The important of reducing a chance of the information being detected during the transmission is being an issue in the real world now days. The Digital watermarking method provides for the quick and inexpensive distribution of digital information over the Internet. This method provides new ways of ensuring the sufficient protection of copyright holders in the intellectual property dispersion process. The property of digital watermarking images allows insertion of additional data in the image without altering the value of the image.In this paper investigate the following relevant concepts and terminology, history of watermarks and the properties of a watermarking system and applications. We are proposing edge detection using Gabor Filters. In this paper we are proposed least significant bit (LSB) substitution method to encrypt the message in the watermark image file. The benefits of the LSB ...

Authors are more often being held responsible for readying their own data figures for digital publication by scanning them at the proper resolution and preparing them for presentation in both print and on-line journals. In this manner, the visuals can be printed at the highest quality the publisher can provide and be ready for rapid electronic distribution on the Internet. Therefore, authors must become knowledgeable in the visual preparation process in order to generate electronic images that will be as true a representation of the original image as possible. Perfecting this procedure can be a learning experience and often requires some experimentation. When accomplished, the author will have more control of exactly how the images will look before they are published. In addition to the scan resolution, the type of digital scanner and software applications used are very important, and instruction manuals should be followed closely so as to understand the full potential of the digitizing equipment. Anat Rec (New Anat): 257:128-136, 1999.

A digital radiography system using self scanning linear diode arrays is being developed for improved diagnosis at reduced radiation dose. Our technique is based on the use of solid state sensors with 1024 diodes per inch and with very high dynamic range. The slit geometry of our method results in image improvement and dose reduction by efficiently rejecting scattered x-rays in the patient. In our present configuration the images have a field of view of six inches by six inches or 6 inches by 12 inches and are digitized to 1024 x 1024 pixels with 12 bits. This digital system differs from the conventional digital radiography in that no image intensifier TV fluoroscopy chain is required. Preliminary clinical studies have demonstrated the high detail of our system at low radiation levels. In dog studies the system has clearly visualized very small coronary arteries following aortic root injection of contrast material. Even with intravenous injections some of the coronary arteries could be seen.

Image processing plays an important role in optimizing image quality and radiation dose in projection radiography. Unfortunately commercial algorithms are black boxes that are often left at or near vendor default settings rather than being optimized. We hypothesize that different commercial image-processing systems, when left at or near default settings, create significant differences in image quality. We further hypothesize that image-quality differences can be exploited to produce images of equivalent quality but lower radiation dose. We used a portable radiography system to acquire images on a neonatal chest phantom and recorded the entrance surface air kerma (ESAK). We applied two image-processing systems (Optima XR220amx, by GE Healthcare, Waukesha, WI; and MUSICA{sup 2} by Agfa HealthCare, Mortsel, Belgium) to the images. Seven observers (attending pediatric radiologists and radiology residents) independently assessed image quality using two methods: rating and matching. Image-quality ratings were independently assessed by each observer on a 10-point scale. Matching consisted of each observer matching GE-processed images and Agfa-processed images with equivalent image quality. A total of 210 rating tasks and 42 matching tasks were performed and effective dose was estimated. Median Agfa-processed image-quality ratings were higher than GE-processed ratings. Non-diagnostic ratings were seen over a wider range of doses for GE-processed images than for Agfa-processed images. During matching tasks, observers matched image quality between GE-processed images and Agfa-processed images acquired at a lower effective dose (11 ± 9 μSv; P < 0.0001). Image-processing methods significantly impact perceived image quality. These image-quality differences can be exploited to alter protocols and produce images of equivalent image quality but lower doses. Those purchasing projection radiography systems or third-party image-processing software should be aware that image

We demonstrate that stacking several imaging plates (IPs) constitutes an easy method to increase hard x-ray detection efficiency. Used to record x-ray radiographicimages produced by an intense-laser driven hard x-ray backlighter source, the IP stacks resulted in a significant improvement of the radiograph density resolution. We attribute this to the higher quantum efficiency of the combined detectors, leading to a reduced photon noise. Electron-photon transport simulations of the interaction processes in the detector reproduce the observed contrast improvement. Increasing the detection efficiency to enhance radiographicimaging capabilities is equally effective as increasing the x-ray source yield, e.g., by a larger drive laser energy.

We demonstrate that stacking several imaging plates (IPs) constitutes an easy method to increase hard x-ray detection efficiency. Used to record x-ray radiographicimages produced by an intense-laser driven hard x-ray backlighter source, the IP stacks resulted in a significant improvement of the radiograph density resolution. We attribute this to the higher quantum efficiency of the combined detectors, leading to a reduced photon noise. Electron-photon transport simulations of the interaction processes in the detector reproduce the observed contrast improvement. Increasing the detection efficiency to enhance radiographicimaging capabilities is equally effective as increasing the x-ray source yield, e.g., by a larger drive laser energy.

Mammography is an essential tool for diagnosis and early detection of breast cancer if it is provided as a very good quality service. The process of evaluating the quality of radiographicimages in general, and mammography in particular, can be much more accurate, practical and fast with the help of computer analysis tools. This work compare the automated methodology for the evaluation of scanned digitalimages the phantom mama. By applied the DIP method techniques was possible determine geometrical and radiometric images evaluated. The evaluated parameters include circular details of low contrast, contrast ratio, spatial resolution, tumor masses, optical density and background in Phantom Mama scanned and digitizedimages. The both results of images were evaluated. Through this comparison was possible to demonstrate that this automated methodology is presented as a promising alternative for the reduction or elimination of subjectivity in both types of images, but the Phantom Mama present insufficient parameters for spatial resolution evaluation. (author)

The introduction of endoscopical surgery has among other things influenced technical developments in surgery. Owing to digitalisation, major progress will be made in imaging and in the sophisticated technology sometimes called robotics. Digital storage makes the results of imaging diagnostics (e.g. the results of radiological examination) suitable for transmission via video conference systems for telediagnostic purposes. The availability of digital video technique renders possible the processing, storage and retrieval of moving images as well. During endoscopical operations use may be made of a robot arm which replaces the camera man. The arm does not grow tired and provides a stable image. The surgeon himself can operate or address the arm and it can remember fixed image positions to which it can return if ordered to do so. The next step is to carry out surgical manipulations via a robot arm. This may make operations more patient-friendly. A robot arm can also have remote control: telerobotics. At the Internet site of this journal a number of supplements to this article can be found, for instance three-dimensional (3D) illustrations (which is the purpose of the 3D spectacles enclosed with this issue) and a quiz (http:@appendix.niwi. knaw.nl).

Many organizations have been interested in understanding if commercially available scanners are adequate for scientifically useful digitization. These scanners range in price from a few hundred to a few tens of thousands of dollars (USD), often with little apparent difference in performance specifications. This paper describes why the underlying technology used in flatbed scanners tends to effectively limit resolutions to the 600-1200 dots per inch (dpi) range and how the overall system Modulation Transfer Function (MTF) can be used to evaluate the quality of the digitized data for the small feature sizes found in astronomical images. Two scanners, the Epson V750 flatbed scanner and the Nikon Cool Scan 9000ED film strip scanner, are evaluated through their Modulation Transfer Functions (MTF). The MTF of the Harvard DASCH scanner is also shown for comparison. The particular goal of this evaluation was to understand if the scanners could be used for digitizing spectral plates at the University of Toronto. The plates of primary interest were about 15 mm (5/8 inch) wide by 180 mm (7~inches) long and ˜50 mm x 80 mm (2 x 3 inches). The results of the MTF work show that the Epson scanner, despite claims of high resolution, is of limited value for scientific imaging of feature sizes below about 50 μm and therefore not a good candidate for digitizing the spectral plates and problematic for scanning direct plates. The Nikon scanner is better and, except for some frustrating limitations in its software, its performance seems to hold promise as a digitizer for spectral plates in the University of Toronto collection.

Full Text Available Introduction: Content Based Image Retrieval (CBIR is a method of image searching and retrieval in a database. In medical applications, CBIR is a tool used by physicians to compare the previous and current medical images associated with patients pathological conditions. As the volume of pictorial information stored in medical image databases is in progress, efficient image indexing and retrieval is increasingly becoming a necessity. Materials and Methods: This paper presents a new content based radiographicimage retrieval approach based on histogram of pattern orientations, namely pattern orientation histogram (POH. POH represents the spatial distribution of five different pattern orientations: vertical, horizontal, diagonal down/left, diagonal down/right and non-orientation. In this method, a given image is first divided into image-blocks and the frequency of each type of pattern is determined in each image-block. Then, local pattern histograms for each of these image-blocks are computed. Results: The method was compared to two well known texture-based image retrieval methods: Tamura and Edge Histogram Descriptors (EHD in MPEG-7 standard. Experimental results based on 10000 IRMA radiography image dataset, demonstrate that POH provides better precision and recall rates compared to Tamura and EHD. For some images, the recall and precision rates obtained by POH are, respectively, 48% and 18% better than the best of the two above mentioned methods. Discussion and Conclusion: Since we exploit the absolute location of the pattern in the image as well as its global composition, the proposed matching method can retrieve semantically similar medical images.

Background: The introduction of digital detectors in the radiology predicted a dose reduction. Due to the dynamic range, radiographs of sufficient quality can be produced with a lower detector air kerma (DAK). However, this reduction was not observed. Some authors indicate a creep towards higher DAK, explained by a better appreciation of the radiographs due to a higher contrast-to-noise ratio. Methodology: To investigate the relation between the DAK and the appreciation of image quality by radiologists, 172 anterior-posterior (AP) radiographs of the knee and 152 radiographs of the pelvis were collected in 19 radiology centres. A Visual Grading Analysis (VGA) with a five-point scale was used to judge the image quality of seven different anatomic structures. The mid-point of the scale (3) was equalized to diagnostic image quality. Six experienced radiologists scored both datasets, in a controlled environment, with ViewDex®. Every observer received instructions and a training dataset. Moreover, twenty radiographs were repeated to determine intra-observer variability. Results: The intra-observer variability was not significant (p>0.05) for both datasets. The knee AP obtained a VGAS score of 3.91, the pelvis AP obtained a VGAS score of 3.71. In both cases, the inter-observer correlation was high and significant. The correlation between the VGAS and the DAK (0.41μGy - 6.18μGy) was not significant in either of the cases; neither did other analysises based on technical parameters. Conclusion: The VGA revealed an image quality higher than diagnostic necessary. Based on the DAK, an overexposure is suspected. The relation between DAK and the appreciation has to be further investigated in detail.

Effective interprofessional communication is intrinsic to safe health care. Despite the identified positive impact of collaborative radiographic interpretation between rural radiographers and referrers, communication difficulties still exist. This article describes the strategies that Australian rural radiographers use for communication of their radiographic opinion to the referring doctor. In a two-phase interpretive doctoral study completed in 2012, data were collected from radiographers working in rural New South Wales, Western Australia and Tasmania using a paper based questionnaire followed by in-depth semistructured interviews. Data were analysed thematically in order to identify, analyse and report the emergent themes. The overarching theme was Patient Advocacy, where in the interest of patient care radiographers took measures to ensure that a referring doctor did not miss radiographic abnormalities. Strong interprofessional relationships enabled direct communication pathways. Interprofessional boundaries shaped by historical hierarchical relationships, together with a lack of confidence and educational preparation for radiographic interpretation result in barriers to direct communication pathways. These barriers prompted radiographers to pursue indirect communication pathways, such as side-stepping and hint and hope. A lack of formal communication pathways and educational preparation for this role has resulted in radiographers playing the radiographer-referrer game to overtly or covertly assist referrers in reaching a radiographic diagnosis. The findings from this study may be used to plan interventions for strengthening interprofessional communication pathways and improve quality of healthcare for patients.

The design of experimental system of digitalimaging system for control parameter is discussed in detail. Signal processing of digital CCD imaging system is first analyzed. Then the real time control of CCD driver and digital processing circuit and man-machine interaction are achieved by the design of digital CCD imaging module and control module. Experimental results indicate that the image quality of CCD experimental system makes a good response to the change of control parameters. The system gives an important base for improving image quality and the applicability of micro imaging system in complex environment.

Ken M. Harrison's latest book is a complete guide for amateur astronomers who want to obtain detailed narrowband images of the Sun using a digital spectroheliograph (SHG). The SHG allows the safe imaging of the Sun without the expense of commercial ‘etalon’ solar filters. As the supporting software continues to be refined, the use of the digital spectroheliograph will become more and more mainstream and has the potential to replace the expensive solar filters currently in use. The early chapters briefly explain the concept of the SHG and how it can produce an image from the solar spectrum. A comparison of the currently available narrow band solar filters is followed by a detailed analysis of the critical design, construction and assembly features of the SHG. The design and optimum layout of the instrument is discussed to allow evaluation of performance. This information explains how to assemble a fully functional SHG using readily available components. The software required to process the images is exp...

Digitalimage correlation is not the intended use for consumer colour cameras, but with care they can be successfully employed in such a role. The main obstacle is the sparsely sampled colour data caused by the use of a colour filter array (CFA) to separate the colour channels. It is shown that the method used to convert consumer camera raw files into a monochrome image suitable for digitalimage correlation (DIC) can have a significant effect on the DIC output. A number of widely available software packages and two in-house methods are evaluated in terms of their performance when used with DIC. Using an in-plane rotating disc to produce a highly constrained displacement field, it was found that the bicubic spline based in-house demosaicing method outperformed the other methods in terms of accuracy and aliasing suppression.

Introduction: Primary bone tumors are rare and require a multidisciplinary approach. Diagnosis involves primarily the radiologist and the pathologist. Bone lesions are often heterogeneous and the microscopic diagnostic component(s) may be in the minority, especially on core needle biopsies. Reactive processes, benign, and malignant tumors may have similar microscopic aspects. For these challenging cases, the correlation of microscopic and radiologic information is critical, or diagnostic mistakes may be made with severe clinical consequences for the patient. The purpose of this article is to explain how pathologists can best use imaging studies to improve the diagnostic accuracy of bone lesions. Diagnosis: Many bone lesions are microscopically and/or radiographically heterogeneous, especially those with both lytic and matrix components. Final diagnosis may require specific microscopic diagnostic features that may be present in the lesion, but not the biopsy specimen. A review of the imaging helps assess if sampling was adequate. The existence of a pre-existing bone lesion, syndrome (such as Ollier disease or multiple hereditary exostosis), or oncologic history may be of crucial importance. Finally, imaging information is very useful for the pathologist to perform accurate local and regional staging during gross examination. Conclusion: Close teamwork between pathologists, radiologists, and clinicians is of utmost importance in the evaluation and management of bone tumors. These lesions can be very difficult to interpret microscopically; imaging studies therefore play a crucial role in their accurate diagnosis.

Image processing plays an important role in optimizing image quality and radiation dose in projection radiography. Unfortunately commercial algorithms are black boxes that are often left at or near vendor default settings rather than being optimized. We hypothesize that different commercial image-processing systems, when left at or near default settings, create significant differences in image quality. We further hypothesize that image-quality differences can be exploited to produce images of equivalent quality but lower radiation dose. We used a portable radiography system to acquire images on a neonatal chest phantom and recorded the entrance surface air kerma (ESAK). We applied two image-processing systems (Optima XR220amx, by GE Healthcare, Waukesha, WI; and MUSICA(2) by Agfa HealthCare, Mortsel, Belgium) to the images. Seven observers (attending pediatric radiologists and radiology residents) independently assessed image quality using two methods: rating and matching. Image-quality ratings were independently assessed by each observer on a 10-point scale. Matching consisted of each observer matching GE-processed images and Agfa-processed images with equivalent image quality. A total of 210 rating tasks and 42 matching tasks were performed and effective dose was estimated. Median Agfa-processed image-quality ratings were higher than GE-processed ratings. Non-diagnostic ratings were seen over a wider range of doses for GE-processed images than for Agfa-processed images. During matching tasks, observers matched image quality between GE-processed images and Agfa-processed images acquired at a lower effective dose (11 ± 9 μSv; P Image-processing methods significantly impact perceived image quality. These image-quality differences can be exploited to alter protocols and produce images of equivalent image quality but lower doses. Those purchasing projection radiography systems or third-party image-processing software should be aware that image

Full Text Available We have proposed and tested a novel method for digitalimage sharpening. The method is based on multi-scale image analysis, calculation of differential responses of image brightness in different spatial scales, and the subsequent calculation of a restoration function, which sharpens the image by simple subtraction of its brightness values from those of the original image. The method features spatial transposition of the restoration function elements, its normalization, and taking into account the sign of the brightness differential response gradient close to the object edges. The calculation algorithm for the proposed method makes use of integer arithmetic that significantly reduces the computation time. The paper shows that for the images containing small amount of the blur due to the residual aberrations of an imaging system, only the first two scales are needed for the calculation of the restoration function. Similar to the blind deconvolution, the method requires no a priori information about the nature and magnitude of the blur kernel, but it is computationally inexpensive and is much easier in practical implementation. The most promising applications of the method are machine vision and surveillance systems based on real-time intelligent pattern recognition and decision making.

Full Text Available The research analyzed the relationships and communication links between overproduced images on digital media and their carriers. I start from the hypothesis that the way we look, record, save and access images have been deeply modified with the advent of digital cameras and ‘phone cameras’ – encouraging an addictive behavior for pictures. The method was based on interviews with ten informers – the images’ carriers, who let us conclude that we are overproducing pictures as information. In this context arise the producers of endless everyday pictures, here named ‘photomaniacs’, who give birth two kinds of images: the circulatory infoimages and the everyday infoimages. Overproduced digitalimages transform devices in our magnifiers of memory and oblivion, undoing the way we compile, save or file – and operating in cumulative, disordered, small and private stock of images. Thus, we try to saturate our most superficial memory, that generates schizophrenic pictures when operates on excess. However, even if the way is only technological, we must remember that the body is the living organism suitable to pictures, the place where we hold deep bonding relations. Over this body surface, images survive impregnated of meanings, links, belonging and healing. The research was based on the theories of communication links of Boris Cyrulnik, Jose Ângelo Gaiarsa and Ashley Montagu, besides the works on images and schizophrenia of Nise da Silveira and Leo Navratil. The research also activated the central European stream of Cultural Semiotics, specially the theories of images proposed by Aby Warburg, Walter Benjamin, Dietmar Kamper, Norval Baitello Junior, Hans Belting and Vilém Flusser.

In making a pathologic diagnosis, a pathologist uses cognitive processes: perception, attention, memory, and search (Pena and Andrade-Filho, 2009). Typically, this involves focus while panning from one region of a slide to another, using either a microscope in a traditional workflow or software program and display in a digital pathology workflow (DICOM Standard Committee, 2010). We theorize that during panning operation, the pathologist receives information important to diagnosis efficiency and/or correctness. As compared to an optical microscope, panning in a digital pathology image involves some visual artifacts due to the following: (i) the frame rate is finite; (ii) time varying visual signals are reconstructed using imperfect zero-order hold. Specifically, after pixel's digital drive is changed, it takes time for a pixel to emit the expected amount of light. Previous work suggests that 49% of navigation is conducted in low-power/overview with digital pathology (Molin et al., 2015), but the influence of display factors has not been measured. We conducted a reader study to establish a relationship between display frame rate, panel response time, and threshold panning speed (above which the artifacts become noticeable). Our results suggest visual tasks that involve tissue structure are more impacted by the simulated panning artifacts than those that only involve color (e.g., staining intensity estimation), and that the panning artifacts versus normalized panning speed has a peak behavior which is surprising and may change for a diagnostic task. This is work in progress and our final findings should be considered in designing future digital pathology systems.

A conventional high-resolution screen-film system was compared with a digital detector system. A total of 20 birds (14 pigeons and six psittacine birds) with an average body mass of 533g were examined in dorsoventral as well as lateral projections. Digitalradiographs were acquired with the same mAs as well as half the mAs used for the conventional radiographs. Three criteria and one overall assessment were defined for each of four anatomic regions and assessed by five veterinarians using a score system. Comparison of the ratings was done by visual grading analysis. For the majority of criteria, there was no significant difference regarding image quality between the digital and screen-film projections. However, for certain criteria the quality of the digitalimages was significantly superior. Using the same mAs as for the conventional radiographs, the humeral joint surfaces and the honeycomb structure of the lung were assessed as superior with the digitalimaging system. The tracheal rings and the delineation of the trachea from the surrounding tissue were also superior with the digital system. Assessment of the trabecular structure of the humerus was superior when the full mAs was used compared with the reduced mAs. In conclusion the digital technique is equal or superior to the conventional screen-film high-resolution system for pet birds of a medium size. With some limitations, a dose reduction is possible with the digital system.

In this study the quality of digital and analog radiography in dogs was compared. For this purpose, three conventional radiographs (varying in exposure) and three digitalradiographs (varying in MUSI-contrast [MUSI = MUlti Scale Image Contrast], the main post-processing parameter) of six different body regions of the dog were evaluated (thorax, abdomen, skull, femur, hip joints, elbow). The quality of the radiographs was evaluated by eight veterinary specialists familiar with radiographicimages using a questionnaire based on details of each body region significant in obtaining a radiographic diagnosis. In the first part of the study the overall quality of the radiographs was evaluated. Within one region, 89.5% (43/48) chose a digitalradiograph as the best image. Divided into analog and digital groups, the digitalimage with the highest MUSI-contrast was most often considered the best, while the analog image considered the best varied between the one with the medium and the one with the longest exposure time. In the second part of the study, each image was rated for the visibility of specific, diagnostically important details. After summarisation of the scores for each criterion, divided into analog and digitalimaging, the digitalimages were rated considerably superior to conventional images. The results of image comparison revealed that digitalradiographs showed better image detail than radiographs taken with the analog technique in all six areas of the body.

Accurate scintigraphic determination of organ dimensions is often difficult because of the wide variety of camera-collimator combinations and display formats used for imaging. An algorithm (SPACE-CAL) was developed for digital spatial calibration of up to six large- or small-field gamma cameras using various collimators and magnification factors. The algorithm employs a master calibration file that can be used at multiple terminals. An interactive subroutine permits the operator to measure distances and areas directly from the images. Evaluation of three operators' measurements of a pine-tree phantom acquired at various magnifications showed that distances could be measured with a high degree of accuracy. Calculation of ejection fraction from end-diastolic and end-systolic areas determined by SPACE-CAL showed a high correlation with automatic count determinations (r=0.96) and angiographic calculations (r=0.93) of ejection fraction in 12 patients. SPACE-CAL provides an easily implemented, reproducible, and rapid method for accurate analysis of organ dimensions in digitalimages.

Full Text Available The main objective of the facial edema evaluation is providing the needed information to determine the effectiveness of the anti-inflammatory drugs in development. This paper presents a system that measures the four main variables present in facial edemas: trismus, blush (coloration, temperature, and inflammation. Measurements are obtained by using image processing and the combination of different devices such as a projector, a PC, a digital camera, a thermographic camera, and a cephalostat. Data analysis and processing are performed using MATLAB. Facial inflammation is measured by comparing three-dimensional reconstructions of inflammatory variations using the fringe projection technique. Trismus is measured by converting pixels to centimeters in a digitally obtained image of an open mouth. Blushing changes are measured by obtaining and comparing the RGB histograms from facial edema images at different times. Finally, temperature changes are measured using a thermographic camera. Some tests using controlled measurements of every variable are presented in this paper. The results allow evaluating the measurement system before its use in a real test, using the pain model approved by the US Food and Drug Administration (FDA, which consists in extracting the third molar to generate the facial edema.

The quality of the surface pattern and selection of subset size play a critical role in achieving high accuracy in DigitalImage Correlation (DIC). The subset size in DIC is normally selected by testing different subset sizes across the entire image, which is a laborious procedure. This also leads to the problem that the worst region of the surface pattern influences the performance of DIC across the entire image. In order to avoid these limitations, a Dynamic Subset Selection (DSS) algorithm is proposed in this paper to optimize the subset size for each point in an image before optimizing the correlation parameters. The proposed DSS algorithm uses the local pattern around the point of interest to calculate a parameter called the Intensity Variation Ratio (Λ), which is used to optimize the subset size. The performance of the DSS algorithm is analyzed using numerically generated images and is compared with the results of traditional DIC. Images obtained from laboratory experiments are also used to demonstrate the utility of the DSS algorithm. Results illustrate that the DSS algorithm provides a better alternative to subset size "guessing" and finds an appropriate subset size for each point of interest according to the local pattern.

The modern digital computer has made practical image processing techniques for handling nonlinear operations in both the geometrical and the intensity domains, various types of nonuniform noise cleanup, and the numerical analysis of pictures. An initial requirement is that a number of anomalies caused by the camera (e.g., geometric distortion, MTF roll-off, vignetting, and nonuniform intensity response) must be taken into account or removed to avoid their interference with the information extraction process. Examples illustrating these operations are discussed along with computer techniques used to emphasize details, perform analyses, classify materials by multivariate analysis, detect temporal differences, and aid in human interpretation of photos.

Current guidelines quote tolerances for automatic exposure control (AEC) device performance for X-ray systems as 'Baseline ± X %'. However, in the situation where a baseline figure has not yet been achieved, as in the case of commissioning assessments, this tolerance is not relevant. The purpose of this work is to provide mean doses for direct digital radiography (DDR) X-ray system, operating in AEC, against which comparisons can be made. Dose measurements have been recorded under AEC operation on 29 DDR detectors from three different manufacturers. Two different testing protocols were examined: (1) water equivalent phantoms in front of the DDR detector and (2) aluminium block at the tube head. The average patient exit dose, using the aluminium block was 4.6 μGy with the antiscatter grid in place and 4.0 μGy with the grid removed. Using the water phantoms, the average dose was measured at 17.1 μGy with the antiscatter grid in place and 5.4 μGy with grid removed. Based on these results, it is clear that different testing configurations significantly impact on the measured dose.

For digital X-ray detectors, the need to control factory yield and cost invariably leads to the presence of some defective pixels. Recently, a standard procedure was developed to identify such pixels for industrial applications. However, no quality standards exist in medical or industrial imaging regarding the maximum allowable number and size of detector defects. While the answer may be application specific, the minimum requirement for any defect specification is that the diagnostic quality of the images be maintained. A more stringent criterion is to keep any changes in the images due to defects below the visual threshold. Two highly sensitive image simulation and evaluation methods were employed to specify the fraction of allowable defects as a function of defect cluster size in general radiography. First, the most critical situation of the defect being located in the center of the disease feature was explored using image simulation tools and a previously verified human observer model, incorporating a channelized Hotelling observer. Detectability index d' was obtained as a function of defect cluster size for three different disease features on clinical lung and extremity backgrounds. Second, four concentrations of defects of four different sizes were added to clinical images with subtle disease features and then interpolated. Twenty observers evaluated the images against the original on a single display using a 2-AFC method, which was highly sensitive to small changes in image detail. Based on a 50% just-noticeable difference, the fraction of allowed defects was specified vs. cluster size.

Conclusion: The findings revealed the use of high kVp, automatic exposure control, correct focus image receptor distance, tight collimation and additional filter resulted in a lower ESD. The ESD and ED obtained in this study were comparable with those reported by other studies and lower than the values recommended by the United Nations Scientific Committee on the Effects of Atomic Radiation in 2008.

A four-channel digital flash X-ray imaging system has been developed in our lab. The four flash X-ray heads and four detectors can be used to obtain four radiographicimages at four time intervals of an explosion and ballistic trajectory. The cascaded imaging system mainly consists of three parts: (1) a phosphor screen to convert incident X-rays into visible photons; (2) a lens to efficiently collect visible photons emitted by the phosphor screen; and (3) a charge coupled device image sensor to obtain the visible light image. From the analysis of signal and noise propagation, the system is not X-ray quantum-limited, rather the system has secondary quantum sink at the light collecting stage. The construction of the system, theoretical and experimental analysis of performance are presented.

With the rise in whole slide scanner technology, large numbers of tissue slides are being scanned and represented and archived digitally. While digital pathology has substantial implications for telepathology, second opinions, and education there are also huge research opportunities in image computing with this new source of "big data". It is well known that there is fundamental prognostic data embedded in pathology images. The ability to mine "sub-visual" image features from digital pathology slide images, features that may not be visually discernible by a pathologist, offers the opportunity for better quantitative modeling of disease appearance and hence possibly improved prediction of disease aggressiveness and patient outcome. However the compelling opportunities in precision medicine offered by big digital pathology data come with their own set of computational challenges. Image analysis and computer assisted detection and diagnosis tools previously developed in the context of radiographicimages are woefully inadequate to deal with the data density in high resolution digitized whole slide images. Additionally there has been recent substantial interest in combining and fusing radiologic imaging and proteomics and genomics based measurements with features extracted from digital pathology images for better prognostic prediction of disease aggressiveness and patient outcome. Again there is a paucity of powerful tools for combining disease specific features that manifest across multiple different length scales. The purpose of this review is to discuss developments in computational image analysis tools for predictive modeling of digital pathology images from a detection, segmentation, feature extraction, and tissue classification perspective. We discuss the emergence of new handcrafted feature approaches for improved predictive modeling of tissue appearance and also review the emergence of deep learning schemes for both object detection and tissue classification

Digital information and records are vital to the human race regardless of the nationalities and eras in which they were produced. Digitalimage contents are produced at a rapid pace from cultural heritages via digitalization, scientific and experimental data via high speed imaging sensors, national defense satellite images from governments, medical and healthcare imaging records from hospitals, personal collection of photos from digital cameras. With these mass amounts of precious and irreplaceable data and knowledge, what standards technologies can be applied to preserve and yet provide an interoperable framework for accessing the data across varieties of systems and devices? This paper presents an advanced digitalimage archival system by applying the international standard of MPEG technologies to preserve digitalimage content.

This paper proposes to read cinema in the digital age as a new type of image, the neuroimage. Going back to Gilles Deleuze's cinema books and it is argued that the neuro-image is based in the future. The cinema of Alain Resnais is analyzed as a neuro-image and digital cinema .

This paper proposes to read cinema in the digital age as a new type of image, the neuroimage. Going back to Gilles Deleuze's cinema books and it is argued that the neuro-image is based in the future. The cinema of Alain Resnais is analyzed as a neuro-image and digital cinema .

Full Text Available The aim of this collaborative work is to study the uncertainties associated with DigitalImage Correlation techniques (DIC. More specifically, the link between displacement uncertainties and several correlation parameters chosen by the user and relative to the image analysis software and several image characteristics like speckle size and image noise is emphasized. A previous work [1] has been done for situations with spatially fluctuating displacement fields which dealt with mismatch error linked to the discrepancy between the adopted shape function and the real displacement field in the subset. This present work is focused on the ultimate error regime. To ensure that there is no mismatch error, synthetic images of plane rigid body translation have been analysed. DIC softwares developed by or used in the French community were used to study a large number of settings. The first observations are: (a bias amplitude is almost always insensitive to the subset size, (b DIC formulations can be split up into two families. For the first one, the bias amplitude increases with the noise while it remains constant for the second one. For both families, the mean value of the random error increases with the noise level and with the inverse of the subset size. Furthermore, the random error decreases with the radius of the speckle for the first family, while it increases for the second one. These two different behaviours of the tested DIC package are probably due to their underlying DIC formulation (interpolation, correlation criteria, optimisation process.

We designed a two-day laboratory exploration of fundamental concepts in digitalimages for an introductory engineering course at Maui Community College. Our objective was for the students to understand spatial vs. brightness resolution, standard file formats, image tradeoffs, and the engineering design cycle. We used open investigation, question generation, and an engineering design challenge to help our students achieve these learning goals. We also experimented with incorporating Hawaiian language and cultural awareness into our activity. We present our method, student response, and reflections on the success of our design. The 2008 re-design of this activity focused on better incorporating authentic engineering process skills, and on using a rubric for summative assessment of the students' poster presentations. A single file containing all documents and presentations used in this lesson is available online.

The imaging finding of omental cake has been demonstrated in other modalities, such as computed tomography, magnetic resonance imaging, and ultrasonography. However, to the best of our knowledge, the image presentation of omental cake on a routine kidney-ureter-bladder film has not been reported before in the literature. We presented a unique case of a 61-year-old woman, with known advanced cecal colon mucinous adenocarcinoma, presented to our institution with abdominal fullness, poor appetite, and decreased stool passage for 20 days. Physical examination was unremarkable, except distended abdomen. Subsequent study revealed massive post-pigtail catheter drainage ascites with a prominent soft-tissue mass-causing centralization and tethering of focally distended small bowel gas, suggestive of omental cake on plain radiograph. The imaging finding in plain radiograph corresponds to the findings in other imaging modalities, including abdominal sonography and computed tomography. The patient underwent subtotal colectomy and ileostomy during later courses of chemotherapy due to adhesion ileus and possible intraabdominal abscess, and pathologic study confirmed the diagnosis of cecal mucinous adenocarcinoma and peritoneal carcinomatosis. Although the image finding of omental cake on plain radiograph has never been described, this image finding is unique and should be recognized, as it may suggest the presence of omental cake when first identified in the emergency department from patients with abdominal distension and warrant further evaluation to evaluate the underlying cause.

This work proposes a simple, rapid, inexpensive, and non-destructive methodology based on digitalimages and pattern recognition techniques for classification of biodiesel according to oil type (cottonseed, sunflower, corn, or soybean). For this, differing color histograms in RGB (extracted from digitalimages), HSI, Grayscale channels, and their combinations were used as analytical information, which was then statistically evaluated using Soft Independent Modeling by Class Analogy (SIMCA), Partial Least Squares Discriminant Analysis (PLS-DA), and variable selection using the Successive Projections Algorithm associated with Linear Discriminant Analysis (SPA-LDA). Despite good performances by the SIMCA and PLS-DA classification models, SPA-LDA provided better results (up to 95% for all approaches) in terms of accuracy, sensitivity, and specificity for both the training and test sets. The variables selected Successive Projections Algorithm clearly contained the information necessary for biodiesel type classification. This is important since a product may exhibit different properties, depending on the feedstock used. Such variations directly influence the quality, and consequently the price. Moreover, intrinsic advantages such as quick analysis, requiring no reagents, and a noteworthy reduction (the avoidance of chemical characterization) of waste generation, all contribute towards the primary objective of green chemistry.

Remote Sensing DigitalImage Analysis provides the non-specialist with a treatment of the quantitative analysis of satellite and aircraft derived remotely sensed data. Since the first edition of the book there have been significant developments in the algorithms used for the processing and analysis of remote sensing imagery; nevertheless many of the fundamentals have substantially remained the same. This new edition presents material that has retained value since those early days, along with new techniques that can be incorporated into an operational framework for the analysis of remote sensing data. The book is designed as a teaching text for the senior undergraduate and postgraduate student, and as a fundamental treatment for those engaged in research using digitalimage processing in remote sensing. The presentation level is for the mathematical non-specialist. Since the very great number of operational users of remote sensing come from the earth sciences communities, the text is pitched at a leve...

Due to its special characteristics, quality control in digitalradiographic systems is very important, even more than in conventional film-screen systems. Differences between digital and analogical images,a in terms of dynamics range, spatial and contrast resolution, and the flexibility of data post-processing require some actions to maintain clinical images in an optimum quality level. Revision 1 of the Spanish Protocol of Quality Control in Diagnostic Radiology includes a chapter dedicated to the quality control of these digital systems for the acquisition of radiographicimages. In this paper the different parameters for quality control procedures are described. Also some difficulties to be concerned about (absence of levels of tolerance, access to the raw-data images and related information, availability of use anthropomorphic phantoms, etc, etc) are noted, as well as the most significant aspects of the differences in relation to the ana logical systems. (Author) 15 refs.

Compton radiography is an important diagnostic for Inertial Confinement Fusion (ICF), as it provides a means to measure the density and asymmetries of the DT fuel in an ICF capsule near the time of peak compression. The AXIS instrument (ARC (Advanced Radiography Capability) X-ray Imaging System) is a gated detector in development for the National Ignition Facility (NIF), and will initially be capable of recording two Compton radiographs during a single NIF shot. The principal reason for the development of AXIS is the requirement for significantly improved detection quantum efficiency (DQE) at high x-ray energies. AXIS will be the detector for Compton radiography driven by the ARC laser, which will be used to produce Bremsstrahlung X-ray backlighter sources over the range of 50 keV-200 keV for this purpose. It is expected that AXIS will be capable of recording these high-energy x-rays with a DQE several times greater than other X-ray cameras at NIF, as well as providing a much larger field of view of the imploded capsule. AXIS will therefore provide an image with larger signal-to-noise that will allow the density and distribution of the compressed DT fuel to be measured with significantly greater accuracy as ICF experiments are tuned for ignition.

Full Text Available Objective: The aim of this study is to investigate the importanceof the initial radiographies of patients whose firstmedical intervention was made outside the country bordersand recovered after treatment in our hospital.Methods: The patients with maxillofacial trauma due togunshot and shrapnel injuries who were treated by Departmentof Otolaryngology in the last year were examinedretrospectively. Twenty two patients were includedto the study, who had injuries in another country and whowere received initial medical treatments there. The maxillofacialcomputed tomographies of patients which wereperformed before the treatment were evaluated accordingto the direction of movement of bone fracture fragments.Results: The youngest patient was 17 years old and theoldest one was 43 years old. All the patients were male. Itwas observed that all of the patients were referred to ourhospital after the first intervention had been made in othermedical centers. There was no reliable information aboutthe event of injury and type of used weapon. According tothe findings of the radiological images, the directions ofshootings were determined by the evaluation of the directionsof bone fragments in 19 (86.4% patients.Conclusion: The initial radiographicimages of dead ormedically treated patients with bone fractures due to gunshotinjuries, in cases with unidentified origins and injurymechanisms, play an important role in the determinationof the direction of shooting. The wounds have been identifiedwhether they are entry or exit wounds when the directionsof fire are determined.Key words: Gunshot, direction of fire, bone fracture

Compton radiography is an important diagnostic for Inertial Confinement Fusion (ICF), as it provides a means to measure the density and asymmetries of the DT fuel in an ICF capsule near the time of peak compression. The AXIS instrument (ARC (Advanced Radiography Capability) X-ray Imaging System) is a gated detector in development for the National Ignition Facility (NIF), and will initially be capable of recording two Compton radiographs during a single NIF shot. The principal reason for the development of AXIS is the requirement for significantly improved detection quantum efficiency (DQE) at high x-ray energies. AXIS will be the detector for Compton radiography driven by the ARC laser, which will be used to produce Bremsstrahlung X-ray backlighter sources over the range of 50 keV–200 keV for this purpose. It is expected that AXIS will be capable of recording these high-energy x-rays with a DQE several times greater than other X-ray cameras at NIF, as well as providing a much larger field of view of the imploded capsule. AXIS will therefore provide an image with larger signal-to-noise that will allow the density and distribution of the compressed DT fuel to be measured with significantly greater accuracy as ICF experiments are tuned for ignition.

The purpose of this study was to investigate appropriate contrast reference values (CRVs) by comparing the contrast in phantom and clinical images. Phantom contrast was measured using two methods: (1) counting the number of visible pits of different depths in an aluminum plate, and (2) obtaining the contrast-to-noise ratio (CNR) for 5 tissue-equivalent materials (porcelain, aluminum, polytetrafluoroethylene [PTFE], polyoxymethylene [POM], and polymethylmethacrylate [PMMA]). Four panoramic radiographs of the contrast phantom, embedded in the 4 different regions of the arch-form stand, and 1 real skull phantom image were obtained, post-processed, and compared. The clinical image quality evaluation chart was used to obtain the cut-off values of the phantom CRV corresponding to the criterion of being adequate for diagnosis. The CRVs were obtained using 4 aluminum pits in the incisor and premolar region, 5 aluminum pits in the molar region, and 2 aluminum pits in the temporomandibular joint (TMJ) region. The CRVs obtained based on the CNR measured in the anterior region were: porcelain, 13.95; aluminum, 9.68; PTFE, 6.71; and POM, 1.79. The corresponding values in the premolar region were: porcelain, 14.22; aluminum, 8.82; PTFE, 5.95; and POM, 2.30. In the molar region, the following values were obtained: porcelain, 7.40; aluminum, 3.68; PTFE, 1.27; and POM, - 0.18. The CRVs for the TMJ region were: porcelain, 3.60; aluminum, 2.04; PTFE, 0.48; and POM, - 0.43. CRVs were determined for each part of the jaw using the CNR value and the number of pits observed in phantom images.

BACKGROUND: New developments in processing of digitalradiographs (DR), including multi-frequency processing (MFP), allow optimization of image quality and radiation dose. This is particularly promising in children as they are believed to be more sensitive to ionizing radiation than adults...

A new dual-ported, floating-point, digital signal processor has been evaluated for compressing 512 and 1,024 digitalradiographicimages using a full-frame, two-dimensional, discrete cosine transform (2D-DCT). The floating point digital signal processor operates at 49.5 million floating point instructions per second (MFLOPS). The level of compression can be changed by varying four parameters in the lossy compression algorithm. Throughput times were measured for both 2D-DCT compression and decompression. For a 1,024 x 1,024 x 10-bit image with a compression ratio of 316:1, the throughput was 75.73 seconds (compression plus decompression throughput). For a digital fluorography 1,024 x 1,024 x 8-bit image and a compression ratio of 26:1, the total throughput time was 63.23 seconds. For a computed tomography image of 512 x 512 x 12 bits and a compression ratio of 10:1 the throughput time was 19.65 seconds.

Background Mammography is considered the best imaging technique for breast cancer screening, and the radiographer plays an important role in its performance. Therefore, continuing education is critical to improving the performance of these professionals and thus providing better health care services. Objective Our goal was to develop an e-learning course on breast imaging for radiographers, assessing its efficacy, effectiveness, and user satisfaction. Methods A stratified randomized controlled trial was performed with radiographers and radiology students who already had mammography training, using pre- and post-knowledge tests, and satisfaction questionnaires. The primary outcome was the improvement in test results (percentage of correct answers), using intention-to-treat and per-protocol analysis. Results A total of 54 participants were assigned to the intervention (20 students plus 34 radiographers) with 53 controls (19+34). The intervention was completed by 40 participants (11+29), with 4 (2+2) discontinued interventions, and 10 (7+3) lost to follow-up. Differences in the primary outcome were found between intervention and control: 21 versus 4 percentage points (pp), Pstudents (18 pp vs 5 pp; P=.098). Nonetheless, differences in students’ posttest results were found (88% vs 63%; P=.003), which were absent in pretest (63% vs 63%; P=.106). The per-protocol analysis showed a higher effect (26 pp vs 2 pp; Pstudents (25 pp vs 3 pp; P=.004) and radiographers (27 pp vs 2 pp; Pradiographers, which highlights the need for continuing education. PMID:25560547

This paper discusses the standards, methods, use cases, and opportunities for using embedded metadata in digitalimages. In this paper we explain the past and current work engaged with developing specifications, standards for embedding metadata of different types, and the practicalities of data...... exchange in heritage institutions and the culture sector. Our examples and findings support the case for embedded metadata in digitalimages and the opportunities for such use more broadly in non-heritage sectors as well. We encourage the adoption of embedded metadata by digitalimage content creators...... and curators as well as those developing software and hardware that support the creation or re-use of digitalimages. We conclude that the usability of born digitalimages as well as physical objects that are digitized can be extended and the files preserved more readily with embedded metadata....

Registration of patient anatomical structures to the reference position is a basic part of the patient set-up procedure. Registration of anatomical structures between the site of beam entrance on the patient surface and the distal target position is particularly important. Here, to improve patient positional accuracy during set-up for particle beam treatment, we propose a new visualization methodology using digitally reconstructed radiographs (DRRs), overlaid DRRs, and evaluation of overlaid DRR images in clinical cases. The overlaid method overlays two DRR images in different colors by dividing the CT image into two CT sections at the distal edge of the target along the treatment beam direction. Since our hospital uses fixed beam ports, the treatment beam angles for this study were set at 0 and 90 degrees. The DRR calculation direction was from the X-ray tube to the imaging device, and set to 180/270 degrees and 135/225 degrees, based on the installation of our X-ray imaging system. Original and overlaid DRRs were calculated using CT data for two patients, one with a parotid gland tumor and the other with prostate cancer. The original and overlaid DRR images were compared. Since the overlaid DRR image was completely separated into two regions when the DRR calculation angle was the same as the treatment beam angle, the overlaid DRR visualization technique was able to provide rich information for aiding recognition of the relationship between anatomical structures and the target position. This method will also be useful in patient set-up procedures for fixed irradiation ports.

Background. An audit of paediatric pelvic radiographs identified deficiencies in gonad shield placement and radiographic technique. Objective. A technique using grid-controlled fluoroscopy (GCF), with hard copy images in frame grab and digital spot image (DSI) format was evaluated to optimise gonad shield placement and reduce the dose given to children with Perthes disease and Developmental Hip Dysplasia (DDH) attending for pelvic radiography. Materials and methods. Phantom and patient dose surveys of conventional and fluoroscopic techniques were carried out. Image quality and radiation dose were compared for the frame grab and DSI techniques. Retrospective evaluation was undertaken to compare their clinical acceptability. Results. Both fluoroscopic techniques gave considerably less radiation than conventional non-grid radiography (67-83 %, P < 0.05). The frame grab technique gave less radiation than DSI (P < 0.05). There was no significant difference in the clinical acceptability scores of the DSI and frame grab images. Conclusion. Fluoroscopy acquired images are now used since the fluoroscopic techniques give much less dose than conventional radiography and provide images of sufficient quality for clinical assessment. Indeed, as there was no significant difference in clinical usefulness between the frame grab and DSI techniques, it is planned to use frame grab alone, thus gaining additional dose saving. (orig.)

This paper aims at digital watermark which is a new popular research topic recently, presents some methods to embed digital watermark based on modifying frequency coefficients in discrete wavelettransfor(DWT)domain.First,thepresent progress of digital watermark is briefly introduced; after that, starting from Pitas's method and discarding hispseudo random number method, the authors use a digitalimage scrambling technology as preprocessing fordigital watermarking. Then the authors discuss how to embed a 1-bit digitalimage as watermark in frequency domain. Finallyanotherdigital watermarking method is given in which 3-D DWT is used to transformagivendigitalimage.Basedontheexperimentalresults, it is shown that the proposed methods are robust to a large extent.

Full Text Available Adequate graphic recording has been one of the main objectives of rock art research. Photography has increased its role as a documentary technique. Now, digitalimage and its treatment allows new ways to observe the details of the figures and to develop a recording procedure which is as, or more, accurate than direct tracing. This technique also avoid deterioration of the rock paintings. The mathematical basis of this method is also presented.

Full Text Available Noise is always presents in digitalimages during image acquisition, coding, transmission, and processing steps. Noise is very difficult to remove it from the digitalimages without the prior knowledge of noise model. That is why, review of noise models are essential in the study of image denoising techniques. In this paper, we express a brief overview of various noise models. These noise models can be selected by analysis of their origin. In this way, we present a complete and quantitative analysis of noise models available in digitalimages.

Synopsis This article discusses recent developments in advanced derivative technologies associated with digital mammography. Digital breast tomosynthesis – its principles, development, and early clinical trials are reviewed. Contrast enhanced digital mammography and combined imaging systems with digital mammography and ultrasound are also discussed. Although all these methods are currently research programs, they hold promise for improving cancer detection and characterization if early results are confirmed by clinical trials. PMID:20868894

Foot pathology is a common and important health concern in captive rhinoceroses worldwide, but osteopathologies are rarely diagnosed, partly because of a lack of radiographic protocols. Here, we aimed to develop the first radiographic protocol for rhinoceros feet and describe the radiographic anatomy of the white rhinoceros (Ceratotherium simum) hind foot (pes). Computed tomographic images were obtained of nine cadaver pedes from seven different white rhinoceroses and assessed for pathology. A single foot deemed free of pathology was radiographed using a range of different projections and exposures to determine the best protocol. 3D models were produced from the CT images and were displayed with the real radiographs to describe the normal radiographic anatomy of the white rhinoceros pes. An optimal radiographic projection was determined for each bone in the rhinoceros pes focusing on highlighting areas where pathology has been previously described. The projections deemed to be most useful were D60Pr-PlDiO (digit III), D45Pr45M-PlDiLO (digit II), and D40Pr35L-PlDiLO (digit IV). The primary beam was centered 5-7 cm proximal to the cuticle on the digit of interest. Articular surfaces, ridges, grooves, tubercles, processes and fossae were identified. The radiographic protocol we have developed along with the normal radiographic anatomy we have described will allow for more accessible and effective diagnosis of white rhinoceros foot osteopathologies.

Neutron interrogation provides unique information valuable for Nonproliferation & Materials Control and other important applications including medicine, airport security, protein crystallography, and corrosion detection. Neutrons probe deep inside massive objects to detect small defects and chemical composition, even through high atomic number materials such as lead. However, current detectors are bulky gas-filled tubes or scintillator/PM tubes, which severely limit many applications. Therefore this project was undertaken to develop new semiconductor radiation detection materials to develop the first direct digitalimaging detectors for neutrons. The approach relied on new discovery and characterization of new solid-state sensor materials which convert neutrons directly to electronic signals via reactions BlO(n,a)Li7 and Li6(n,a)T.

This article investigates selected newspapers’ editorial mediations over contrasting perceptions regarding the significance of a controversial set of “iconic” news photographs, namely images of Alan Kurdi, a three-year-old Syrian refugee, whose drowned corpse washed ashore in September, 2015....... Specifically, this study examined individual editorial items, published by leading Danish, Canadian and British newspapers over a four-month period, engaging with and reflecting upon this imagery. Our analysis revealed several key deliberative features of editorial self-reflexivity, with three especially......-reflexivity within a convergent digital media ecology, this article offers original insights into how and why the epistemic values governing visual communication are being reconsidered and redrawn under pressure from institutional imperatives....

With the development of advanced imaging technology, digitalimages are widely used. This paper proposes an automatic quadrilateral mesh generation algorithm for multi-colour imaged structures. It takes an original arbitrary digitalimage as an input for automatic quadrilateral mesh generation, this includes removing the noise, extracting and smoothing the boundary geometries between different colours, and automatic all-quad mesh generation with the above boundaries as constraints. An application example is...

This paper proposes a novel on-line structure lossless compression method for digital mammograms during the film digitization process. The structure-lossless compression segments the breast and the background, compresses the former with a predictive lossless coding method and discards the latter. This compression scheme is carried out during the film digitization process and no additional time is required for the compression. Digital mammograms are compressed on-the-fly while they are created. During digitization, lines of scanned data are first acquired into a small temporary buffer in the scanner, then they are transferred to a large image buffer in an acquisition computer which is connected to the scanner. The compression process, running concurrently with the digitization process in the acquisition computer, constantly checks the image buffer and compresses any newly arrived data. Since compression is faster than digitization, data compression is completed as soon as digitization is finished. On-line compression during digitization does not increase overall digitizing time. Additionally, it reduces the mammogram image size by a factor of 3 to 9 with no loss of information. This algorithm has been implemented in a film digitizer. Statistics were obtained based on digitizing 46 mammograms at four sampling distances from 50 to 200 microns.

A thinning based approach for spatial antialiasing (TAA) has been proposed for visual saliency of digitalimages. This TAA approach is based on edge-matting and digital compositing strategies. Prior to edgematting the image edges are detected using ant colony optimization (ACO) algorithm and then th

A thinning based approach for spatial antialiasing (TAA) has been proposed for visual saliency of digitalimages. This TAA approach is based on edge-matting and digital compositing strategies. Prior to edgematting the image edges are detected using ant colony optimization (ACO) algorithm and then

Supporting safe and resilient authentication and integrity of digitalimages is of critical importance in a time of enormous creation and sharing of these contents. This paper presents an improved digitalimage watermarking model based on a coefficient quantization technique that intelligently encod

Archival digitalimage collections are a relatively new phenomenon in college library archives. Digitizing archival image collections may make them accessible to users worldwide. There has been no study to explore whether collections on the Internet lead to users who are beyond the institution or a comparison of users to a national or…

This article draws on two projects funded by the Andrew W. Mellon Foundation concerning the ways colleges and universities can support the legitimate sharing of digital learning resources for scholarly use. The 2001-03 Visual Image User Study (VIUS) assessed the scholarly needs of digitalimage users-faculty, staff, and students. That study led to…

New developments in processing of digitalradiographs (DR), including multi-frequency processing (MFP), allow optimization of image quality and radiation dose. This is particularly promising in children as they are believed to be more sensitive to ionizing radiation than adults. To examine whether the use of MFP software reduces the radiation dose without compromising quality at DR of the femur in 5-year-old-equivalent anthropomorphic and technical phantoms. A total of 110 images of an anthropomorphic phantom were imaged on a DR system (Canon DR with CXDI-50 C detector and MLT[S] software) and analyzed by three pediatric radiologists using Visual Grading Analysis. In addition, 3,500 images taken of a technical contrast-detail phantom (CDRAD 2.0) provide an objective image-quality assessment. Optimal image-quality was maintained at a dose reduction of 61% with MLT(S) optimized images. Even for images of diagnostic quality, MLT(S) provided a dose reduction of 88% as compared to the reference image. Software impact on image quality was found significant for dose (mAs), dynamic range dark region and frequency band. By optimizing image processing parameters, a significant dose reduction is possible without significant loss of image quality. (orig.)

This paper presents digitalimage fusion (enhanced A+B) systems in color imaging and low light target applications. This paper will discuss first the digital sensors that are utilized in the noted image fusion applications which is a 1900x1086 (high definition format) CMOS imager coupled to a Generation III image intensifier for the visible/near infrared (NIR) digital sensor and 320x240 or 640x480 uncooled microbolometer thermal imager for the long wavelength infrared (LWIR) digital sensor. Performance metrics for these digitalimaging sensors will be presented. The digitalimage fusion (enhanced A+B) process will be presented in context of early fused night vision systems such as the digitalimage fused system (DIFS) and the digital enhanced night vision goggle and later, the long range digitally fused night vision sighting system. Next, this paper will discuss the effects of user display color in a dual color digitalimage fusion system. Dual color image fusion schemes such as Green/Red, Cyan/Yellow, and White/Blue for image intensifier and thermal infrared sensor color representation, respectively, are discussed. Finally, this paper will present digitally fused imagery and image analysis of long distance targets in low light from these digital fused systems. The result of this image analysis with enhanced A+B digitalimage fusion systems is that maximum contrast and spatial resolution is achieved in a digital fusion mode as compared to individual sensor modalities in low light, long distance imaging applications. Paper has been cleared by DoD/OSR for Public Release under Ref: 08-S-2183 on August 8, 2008.

Digitalimaging has been widely used in the field of oral and maxillofacial radiology. The present work summarizes the use of digitalimaging from the following aspects: ①The origin of digital oral and maxillofacial imaging; ②The influence of digitalimaging on the work mode and work flow of oral and maxillofacial radiology; ③ Application of picture archiving and communication system(PACS)in oral and maxillofacial radiology; ④The influence of three dimensional medical data sets on diagnosis, prognosis and treatment plan; ⑤Digitalimaging facilitates the development of telemedicine and internet-medicine; ⑥The significance of establishing a medical database or data center; ⑦Problems and challenges.

There is high demand for quick digitization and subsequent image restoration of archived film records. Digitization is very urgent in many cases because various invaluable pieces of cultural heritage are stored on aging media. Only selected records can be reconstructed perfectly using painstaking manual or semi-automatic procedures. This paper aims to answer the question what are the quality requirements on the restoration process in order to obtain acceptably close visual perception of the digitally restored film in comparison to the original analog film copy. This knowledge is very important to preserve the original artistic intention of the movie producers. Subjective experiment with artificially distorted images has been conducted in order to answer the question what is the visual impact of common image distortions in digital cinema. Typical color and contrast distortions were introduced and test images were presented to viewers using digital projector. Based on the outcome of this subjective evaluation a system for objective assessment of image distortions has been developed and its performance tested. The system utilizes calibrated digital single-lens reflex camera and subsequent analysis of suitable features of images captured from the projection screen. The evaluation of captured image data has been optimized in order to obtain predicted differences between the reference and distorted images while achieving high correlation with the results of subjective assessment. The system can be used to objectively determine the difference between analog film and digital cinema images on the projection screen.

Full Text Available Radiography is one of the oldest NDT technique used for evaluation of weld defects in metal. Radiographic defects are classified based on the shape, location, orientation, depth, width etc. Once a radiographof a weld is taken, the radiographer examines the same for identifying the defects and quantitatively evaluating the same based on codes and specifications. In recent years digitalimaging has superseded conventional imaging, which has led to a profound change in interpretation of radiographicimages. A change in the Gray values of the digitalimage (edges indicates the flaws on the radiographicimage. This paper discusses the Gray level distribution of a test piece radiograph. The test piece considered is a stainless steel metal plate on which a square hole is drilled with different area and depth. The plate is radiographed using X-ray and gamma rays (IR192.

Exosomes, which are membranous nanovesicles, are actively released by cells and have been attributed to roles in cell-cell communication, cancer metastasis, and early disease diagnostics. The small size (30–100 nm) along with low refractive index contrast of exosomes makes direct characterization and phenotypical classification very difficult. In this work we present a method based on Single Particle Interferometric Reflectance Imaging Sensor (SP-IRIS) that allows multiplexed phenotyping and digital counting of various populations of individual exosomes (>50 nm) captured on a microarray-based solid phase chip. We demonstrate these characterization concepts using purified exosomes from a HEK 293 cell culture. As a demonstration of clinical utility, we characterize exosomes directly from human cerebrospinal fluid (hCSF). Our interferometric imaging method could capture, from a very small hCSF volume (20 uL), nanoparticles that have a size compatible with exosomes, using antibodies directed against tetraspanins. With this unprecedented capability, we foresee revolutionary implications in the clinical field with improvements in diagnosis and stratification of patients affected by different disorders. PMID:27853258

Some authors mention that it is not possible to detect early bone metastasis on plain radiography. In this work we use digitalimaging processing to analyze three radiographs taken from a patient with bone metastasis discomfort on the right shoulder. The time period among the first and second radiography was approximately one month and between the first and the third one year. This procedure is a first approach in order to know if in this particular case it was possible to detect an early bone metastasis. The obtained results suggest that by carrying out a digital processing is possible to detect the metastasis since the radiography contains the information although visually it is not possible to observe it.

The objectives of this communication were to discuss radiographic and magnetic resonance (MR) imaging manifestations and clinical outcome after complete and incomplete resection of the mass of dysplasia epiphysealis hemimelica (DEH). Clinical records, radiographs, and MR images of eight patients with DEH were retrospectively examined. Six patients were treated by complete excision of the lesional mass, and two patients were treated by incomplete resection at our University Hospitals during the period from 1980 to 2006. We found that, unlike in osteochondroma, DEH was radiographically not clearly separable from the underlying or host bone with preserved cortical bone and marrow continuity. The finding in the talus distinguished DEH from (osteochondroma-like) parosteal osteosarcoma, in which a radiolucent demarcation line clearly separated the tumor from the host bone. The DEH mass had a well-defined low to intermediate signal intensity on T1-weighted images and an intermediate to high signal intensity on T2-weighted images, with irregularity of the articular surface. Simple excision was performed in all patients. The excision was complete in six patients and incomplete in two patients whose lesions was juxta-articular in the ankle and articular in the knee, respectively. The residual mass slowly absorbed and vanished, resulting in mild flaring of the affected portion of the epiphysis. No local recurrence or complication was seen in any of the eight patients. Although the radiographic signs of DEH are characteristic, (osteochondroma-like) parosteal osteosarcoma should be differentiated from DEH when there is a radiolucent separation line between the mass and host bone in the talus. Simple excision was effective in the management of DEH if the deformity was not complicated. Incompletely excised masses resolved and vanished with time. (orig.)

Human identification requires comparison of individual traits of a person, depending on the availability and reproduction of antemortem (AM) records. If there is no presumed identity or AM exams are not available for comparison, the production of postmortem (PM) records is impaired. The purpose of this research is to describe and test standards to enable the comparison of antemortem periapical radiographs to images extracted from the manipulation of postmortem CBCT exams in multiple identification simulations in a randomized blind study. In a simulation, 20 CBCT images from dry skulls were used as PM records and 3 periapical radiographs (total of 60) that were randomized and blinded from the first examiner. In each case, an intentional incidence error of 10° was added in four different directions. Three points were selected in the AM radiograph, and the angle, linear measurements and proportion between these distances were collected. The AM data were used to mathematically find similar image geometry on a CBCT maximum intensity projection. Possible identification by superimposition was achieved in all cases, and statistical analysis proved the success in the reproduction of angular and length proportion using CBCT incidence manipulation. Significant reproducibility was also observed on intra- and inter-observer tests. In conclusion, the images extracted from CBCT could be compared to any periapical radiographs by superimposition, providing acceptable evidence to establish human identification. The application of this protocol is suitable for forensic practices with the high level of reproducibility and could be used as PM record when no AM records are available at the time of the exam.

ICRP 103 specifies reference dose levels to be used during radiographic exams. Usually, the radiographer qualitative determines the best radiographic technique (kV and mAs) in order to obtain better image quality with the lowest dose. The objective of this study was to evaluate the doses used in examination of the chest, abdomen and skull in patients of different physical sizes, and infer about the amount of dose required to maintain acceptable radiological contrast in patients of different physical sizes. Techniques used by experienced radiographers of HC-FMB-UNESP for examinations of the chest (PA), abdomen (AP) and skull (AP) for patients of different thickness (small, medium and thick body) were obtained. Dose measurements were performed referring to all kV/mAs combinations. PMMA phantoms were placed below the ionization chamber. The Signal Difference Noise Ratio (SDNR) of the images of the phantoms were calculated from an area of contrast and a region of normal tissue. The Figure of Merit (FoM) was calculated for each of the exam modality. Measured FoM decreased according to the thickness of the chest and abdomen, indicating the need to increase the dose level to maintain the same level of image contrast. Patients thicker usually end up getting more than twice the dose of lean patients. Required image quality levels for correct diagnosis should be obtained using dose levels as low as reasonably practicable examination. These factors highlight the need for a program of quality assurance and effective dose studies in actual service. (author)

Good morning ladies and gentlemen. I represent Polaroid Graphics Imaging, a wholly owned subsidiary of the Polaroid Corporation. We wish to thank Ken Cloud and the SPIE for the opportunity to speak today. Several criterion are fundamental in the role for Direct Digital Color Proofing (DDCP), First, the DDCP must represent a first generation hardcopy of the exact color information in the production stream. If must, as it's name suggests be an exact, proof (hence the name direct) of the electronic or digital information which would otherwise be directed toward film working. It is after all the most critical means to evaluate the quality of whatever pagination, scanner or color work which has gone be for it. Second, the DDCP must represent an opportunity. That opportunity is to reconvene the production stream and move to film making, optical or magnetic storage, or satellite transmission with the confidence that the DDCP is identical to some conventional counterpart. In the case of film it must match a conventional proof and press sheet, dot for dot. Otherwise it is merely an exercise in interpretation. For magnetic or optical storage and satellite transmission there must be assurance that at any opportunity either a duplicate DDCP or a conventional film/proof could reproduce earlier results. Finally as the printed product is the final goal and direct to press is evolving in direct to plate and direct to gravure printing the DDCP must share the half toner lineage of these products. Thirdly and hardly least, the whole purpose for DDCP is increased productivity. However, our industry struggles to maintain individuality and variety. Somehow DDCP must balance these forces.

The purpose of this study was to compare the accuracy of postoperative maxillary cyst (POMC) diagnosis by panoramic radiographs versus computed tomography (CT) and by oral and maxillofacial radiologists versus non-specialists. Sixty-five maxillary sinuses with POMCs and 63 without any lesion were assessed using panoramic radiographs and CT images by five oral and maxillofacial radiologists and five non-specialists on a five-point scale. The areas under receiver operating characteristic (ROC) curves were analyzed to determine the differences in diagnostic accuracy between the two imaging modalities and between the two groups of observers. The intra-observer agreement was determined, too. The diagnostic accuracy of CT images was higher than that of panoramic radiographs in both groups of observers (p<0.05). The diagnostic accuracy of oral and maxillofacial radiologists for each method was higher than that of non-specialists (p<0.05). The use of CT improves the diagnosis of POMC, and radiological training and experience leads to more accurate evaluation.

Full Text Available The Internet as a whole does not use secure links, thus information in transit may be vulnerable to interruption as well. The important of reducing a chance of the information being detected during the transmission is being an issue in the real world now days. The Digital watermarking method provides for the quick and inexpensive distribution of digital information over the Internet. This method provides new ways of ensuring the sufficient protection of copyright holders in the intellectual property dispersion process. The property of digital watermarking images allows insertion of additional data in the image without altering the value of the image. This message is hidden in unused visual space in the image and stays below the human visible threshold for the image. Both seek to embed information inside a cover message with little or no degradation of the cover-object. In this paper investigate the following relevant concepts and terminology, history of watermarks and the properties of a watermarking system as well as a type of watermarking and applications. We are proposing edge detection using Gabor Filters. In this paper we are proposed least significant bit (LSB substitution method to encrypt the message in the watermark image file. The benefits of the LSB are its simplicity to embed the bits of the message directly into the LSB plane of cover-image and many techniques using these methods. The LSB does not result in a human perceptible difference because the amplitude of the change is little therefore the human eye the resulting stego image will look identical to the cover image and this allows high perceptual transparency of the LSB. The spatial domain technique LSB substitution it would be able to use a pseudo-random number generatorto determine the pixels to be used for embedding based on a given key. We are using DCT transform watermark algorithms based on robustness. The watermarking robustness have been calculated by the Peak Signal to

Full Text Available The Internet as a whole does not use secure links, thus information in transit may be vulnerable to interruption as well. The important of reducing a chance of the information being detected during the transmission is being an issue in the real world now days. The Digital watermarking method provides for the quick and inexpensive distribution of digital information over the Internet. This method provides new ways of ensuring the sufficient protection of copyright holders in the intellectual property dispersion process. The property of digital watermarking images allows insertion of additional data in the image without altering the value of the image. This message is hidden in unused visual space in the image and stays below the human visible threshold for the image. Both seek to embed information inside a cover message with little or no degradation of the cover-object. In this paper investigate the following relevant concepts and terminology, history of watermarks and the properties of a watermarking system as well as a type of watermarking and applications. We are proposing edge detection using Gabor Filters. In this paper we are proposed least significant bit (LSB substitution method to encrypt the message in the watermark image file. The benefits of the LSB are its simplicity to embed the bits of the message directly into the LSB plane of cover-image and many techniques using these methods. The LSB does not result in a human perceptible difference because the amplitude of the change is little therefore the human eye the resulting stego image will look identical to the cover image and this allows high perceptual transparency of the LSB. The spatial domain technique LSB substitution it would be able to use a pseudo-random number generator to determine the pixels to be used for embedding based on a given key. We are using DCT transform watermark algorithms based on robustness. The watermarking robustness have been calculated by the Peak Signal

The steady increase of Carbon-Fiber Reinforced Polymer (CFRP) Structures in modern aircraft will reach a new dimension with the entry into service of the Boeing 787 and Airbus 350. Replacement of damaged parts will not be a preferable solution due to the high level of integration and the large size of the components involved. Consequently the need to develop repair techniques and processes for composite components is readily apparent. Bonded patch repair technologies provide an alternative to mechanically fastened repairs with significantly higher performance, especially for relatively thin skins. Carefully designed adhesively bonded patches can lead to cost effective and highly efficient repairs in comparison with conventional riveted patch repairs that cut fibers and introduce highly strained regions. In this work, the assessment of the damage process taking place in notched (open-hole) specimens under uniaxial tensile loading was studied. Two-dimensional (2D) and three-dimensional (3D) DigitalImage Correlation (DIC) techniques were employed to obtain full-field surface strain measurements in carbon-fiber/epoxy T700/M21 composite plates with different stacking sequences in the presence of an open circular hole. Penetrant enhanced X-ray radiographs were taken to identify damage location and extent after loading around the hole. DIC strain fields were compared to finite element predictions. In addition, DIC techniques were used to characterise damage and performance of adhesively bonded patch repairs in composite panels under tensile loading. This part of work relates to strength/stiffness restoration of damaged composite aircraft that becomes more important as composites are used more extensively in the construction of modern jet airliners. The behaviour of bonded patches under loading was monitored using DIC full-field strain measurements. Location and extent of damage identified by X-ray radiography correlates well with DIC strain results giving confidence to

Objectives The aim was to introduce a novel alignment criterion, focus mutual information (FMI), for the superimposition of lateral cephalometric radiographs and three dimensional (3D) cone beam computed images as well as the assessment of the alignment characteristics of the new method and comparison of the novel methodology with the region of interest (ROI) approach. Methods Implementation of a FMI criterion-based methodology that only requires the approximate indication of stable structures in one single image. The robustness of the method was first addressed in a phantom experiment comparing the new technique with a ROI approach. Two consecutive cephalometric radiographs were then obtained, one before and one after functional twin block application. These images were then superimposed using alignment by FMI where the following were focused on, in several ways: (1) cranial base and acoustic meatus, (2) palatal plane and (3) mandibular symphysis. The superimposed images were subtracted and coloured. The applicability to cone beam CT (CBCT) is illustrated by the alignment of CBCT images acquired before and after craniofacial surgery. Results The phantom experiment clearly shows superior alignment when compared to the ROI approach (Wilcoxon n = 17, Z = −3.290, and P = 0.001), and robustness with respect to the choice of parameters (one-sample t-test n = 50, t = −12.355, and P = 0.000). The treatment effects are revealed clearly in the subtraction image of well-aligned cephalometric radiographs. The colouring scheme of the subtraction image emphasises the areas of change and visualizes the remodelling of the soft tissue. Conclusions FMI allows for cephalometry without tracing, it avoids the error inherent to the use of landmarks and the interaction of the practitioner is kept to a minimum. The robustness to focal distribution variations limits the influence of possible examiner inaccuracy. PMID:20395459

Full Text Available The methodology presented here developed out of work required to convert the hard-copy illustrations submitted to Internet Archaeology for publication of the 1975 excavations at Cricklade. The publication (and digitalimage preparatory work was funded by English Heritage and was, in part, an experiment designed to explore some of the possibilities presented by digitalimage publication. Various challenges in how to transform the drawings on permatrace to a digital format were encountered. While a full exploration of the potential of all areas of digitalimage preparation and publication was not possible, some interesting technical options were evaluated. This short article explains the processes applied in creating the images that were finally incorporated within the publication. It also examines some other avenues regarding the presentation of archaeological drawings that could be explored in both future Internet Archaeology content and other digital publications.

The provision of a written comment on traumatic abnormalities of the musculoskeletal system detected by radiographers can assist referrers and may improve patient management, but the practice has not been widely adopted outside the United Kingdom. The purpose of this study was to investigate Australian radiographers' perceptions of their readiness for practice in a radiographer commenting system and their educational preferences in relation to two different delivery formats of image interpretation education, intensive and non-intensive. A cross-sectional web-based questionnaire was implemented between August and September 2012. Participants included radiographers with experience working in emergency settings at four Australian metropolitan hospitals. Conventional descriptive statistics, frequency histograms, and thematic analysis were undertaken. A Wilcoxon signed-rank test examined whether a difference in preference ratings between intensive and non-intensive education delivery was evident. The questionnaire was completed by 73 radiographers (68% response rate). Radiographers reported higher confidence and self-perceived accuracy to detect traumatic abnormalities than to describe traumatic abnormalities of the musculoskeletal system. Radiographers frequently reported high desirability ratings for both the intensive and the non-intensive education delivery, no difference in desirability ratings for these two formats was evident (z = 1.66, P = 0.11). Some Australian radiographers perceive they are not ready to practise in a frontline radiographer commenting system. Overall, radiographers indicated mixed preferences for image interpretation education delivered via intensive and non-intensive formats. Further research, preferably randomised trials, investigating the effectiveness of intensive and non-intensive education formats of image interpretation education for radiographers is warranted.

A number of the modern applications such as medical imaging, remote sensing satellites imaging, virtual prototyping etc use the High Dynamic Range Image (HDRI). Generally to obtain HDRI from ordinary digitalimage the camera is calibrated. The article proposes the camera calibration method based on the clear sky as the standard light source and takes sky luminance from CIE sky model for the corresponding geographical coordinates and time. The article considers base algorithms for getting real luminance values from ordinary digitalimage and corresponding programmed implementation of the algorithms. Moreover, examples of HDRI reconstructed from ordinary images illustrate the article.

This book carries forward recent work on visual patterns and structures in digitalimages and introduces a near set-based a topology of digitalimages. Visual patterns arise naturally in digitalimages viewed as sets of non-abstract points endowed with some form of proximity (nearness) relation. Proximity relations make it possible to construct uniform topolo- gies on the sets of points that constitute a digitalimage. In keeping with an interest in gaining an understanding of digitalimages themselves as a rich source of patterns, this book introduces the basics of digitalimages from a computer vision perspective. In parallel with a computer vision perspective on digitalimages, this book also introduces the basics of prox- imity spaces. Not only the traditional view of spatial proximity relations but also the more recent descriptive proximity relations are considered. The beauty of the descriptive proximity approach is that it is possible to discover visual set patterns among sets that are non-overlapping ...

Full Text Available This research goes through the instructional possibilities that reading and writing the digitalimage have in Education. Along these lines, we are presenting this research that looks for, on one hand, to develop a methodological proposal for reading and writing the digitalimage, and on the other, to implement these methodologies in a course used as a study case and whose objective was to evaluate students' performance when writing screens for a learning object using the methodologies for reading and writing the digitalimage. The process for compiling date was based on the questionnaire technique, individual interviews and the analysis of course proposed activities. The application of the first questionnaire allowed us to determine students' knowledge level about the digitalimage before starting the course. The individual interview allowed us to determine the students' reading criteria gained after using the reading methodology for the digitalimage to analyse educational materials (Galavis, 2008; Azzato, 2009. The proposed activities for the course permitted us to value students' performance when reading and writing the digitalimage of a learning object. Finally, after course completion, the second questionnaire was applied in order to determine the students' acquired knowledge level about reading and writing an image on digital screens. The results obtained in each of the analysis allowed us to establish that the proposed methodologies were highly useful to write the educational image for the screens of each one of the learning objects created in the course.

- Instrumentarium, digital direct. In the Adobe™ Photoshop program, five cephalometric landmarks were set in the images and the impression in transparencies was made. The indirect digitization of the images was performed through the Sony™ DSC-W5 and Canon™ Rebel XT/EOS 350D digital photographic cameras-fixed in a copy stand, at the distances of 25 cm and 60 cm-and through the Hewlett Packard™ Scan Jet 4C scanner. The direct digitalimages and the indirect ones were inserted and gauged in the Radiocef Studio (Radiomemory™, Brazil software and the center of the previously marked landmarks was set. The cephalometric computerized analysis generated three angular measurements and four linear ones which were submitted to statistical analysis. RESULTS: The images from the scanner demonstrated small statistically significant alterations, without clinical significance. When digitizing the radiographs at 60 cm, both cameras caused distortions which were statistically significant, but clinically acceptable. At 25 cm, the cameras caused the largest distortions, being more expressive and with clinical significance in the images of Canon™ Rebel XT. CONCLUSIONS: The Hewlett Packard™ Scan Jet 4C scanner with transparency reader and the Sony™ DSC-W5 and Canon™ Rebel XT/EOS cameras operating at 60 cm were shown appropriate for the digitization of cephalometric radiographs. In 25 cm, the digital cameras caused distortions in the image which altered the linear measurements with possibilities of jeopardizing the orthodontic diagnosis.

The College of Radiographers state that the role of a Consultant Radiographer comprises four core functions [College of Radiographers. Developing a business case for consultant radiographers. London: College of Radiographers; 2003; Hardy M, Snaith B. How to achieve consultant practitioner status: a discussion paper. Radiography, in press. doi:10.1016/j.radi.2006.04.003 [accessed 16.08.07

Evaluating the health of a mechanism requires more than just a binary evaluation of whether an operation was completed. It requires analyzing more comprehensive, full-field data. Health monitoring is a process of nondestructively identifying characteristics that indicate the fitness of an engineered component. In order to monitor unit health in a production setting, an automated test system must be created to capture the motion of mechanism parts in a real-time and non-intrusive manner. One way to accomplish this is by using high-speed video (HSV) and DigitalImage Correlation (DIC). In this approach, individual frames of the video are analyzed to track the motion of mechanism components. The derived performance metrics allow for state-of-health monitoring and improved fidelity of mechanism modeling. The results are in-situ state-of-health identification and performance prediction. This paper introduces basic concepts of this test method, and discusses two main themes: the use of laser marking to add fiducial patterns to mechanism components, and new software developed to track objects with complex shapes, even as they move behind obstructions. Finally, the implementation of these tests into an automated tester is discussed.

The constant exposure technique has been applied to assess various industrial radiographic systems. Different X-ray films and radiographic papers of two producers were compared. Special attention was given to fast film and paper used with fluorometallic screens. Radiographicimage quality...... was tested by the use of ISO wire IQI's and ASTM penetrameters used on Al and Fe test plates. Relative speed and reduction of kilovoltage obtained with the constant exposure technique were calculated. The advantages of fast radiographic systems are pointed out...

Full Text Available The important epistemic function of photographic images is their active role in construction and reconstruction of our beliefs concerning the world and human identity, since we often consider photographs as presenting reality or even the Real itself. Because photography can convince people of how different social and ethnic groups and even they themselves look, documentary projects and the dissemination of photographic practices supported the transition from disciplinary society to the present-day society of control. While both analog and digitalimages are formed from the same basic materia, the ways in which this matter appears are distinctive. In the case of analog photography, we deal with physical and chemical matter, whereas with digitalimages we face electronic matter. Because digital photography allows endless modification of the image, we can no longer believe in the truthfulness of digitalimages.

Copy-move is considered as one of the most popular kind of digitalimage tempering, in which one or more parts of a digitalimage are copied and pasted into different locations. Geometric transformation is among the major challenges in detecting copy-move forgery of a digitalimage. In such forgery, the copied and moved parts of a forged image are either rotated or/and re-scaled. Hence, in this study we propose a combination of Discrete Wavelet Transform (DWT) and Speeded Up Robust Features (SURF) to detect a copy-move activity. The experiments results prove that the proposed method is superior with overall accuracy 95%. The copy-move attacks in digitalimage has been successfully detected and the method is also can detect the fraud parts exposed to rotation and scaling issue.

The present thesis "Application of DigitalImage Analysis in Experimental Mechanics" has been prepared as a part of Janus Lyngbyes Ph.D. study during the period December 1988 to June 1992 at the Department of Building technology and Structural Engineering, University of Aalborg, Denmark....... In this thesis attention will be focused on optimal use and analysis of the information of digitalimages. This is realized during investigation and application of parametric methods in digitalimage analysis. The parametric methods will be implemented in applications representative for the area of experimental...

The objective was to determine the value of radiographs in young adults with non-acute knee symptoms who are scheduled for magnetic resonance imaging (MRI). Nine hundred and sixty-one consecutive patients aged between 16 and 45 years with knee symptoms of at least 4 weeks' duration were prospectively included in three participating hospitals. After applying exclusion criteria, 798 patients remained. Exclusion criteria were previous knee surgery (including arthroscopy) or MRI, history of rheumatoid arthritis, clinical diagnosis of retropatellar chondromalacia, contra-indication for MRI and recent trauma. We identified two groups: group A with no history of trauma (n = 332), and group B with an old (>4 weeks) history of trauma (n = 466). Patients had a standardized history taken, and underwent a physical exam, antero-posterior (AP) and lateral radiographs and MRI. We evaluated the radiographs and MRI for osseous lesions, articular surface lesions, fractures, osteoarthritis, loose bodies, bone marrow edema and incidental findings. Subsequently, patients with osseous abnormalities (Kellgren grade 1 and 2 excluded) on radiographs and a matched control group was evaluated again using MRI without radiographs. Median duration of symptoms was 20 weeks. In group A, radiographs showed 36 osseous abnormalities in 332 patients (10.8%). Only 13 of these, all Kellgren grade 1 osteoarthritis, were not confirmed on MRI. MRI showed 72 (21.7%) additional abnormalities not confirmed on radiographs. In group B, radiographs showed 40 osseous abnormalities (8.6%) in 466 patients. Only 15 of these, all Kellgren grade 1 osteoarthritis, were not confirmed on MRI. MRI showed 194 (41.6%) additional abnormalities not confirmed on radiographs. The second evaluation of MRI without radiographs in 34 patients was identical to the first MRI evaluation. Common lesions were significantly more often diagnosed with MRI than with radiographs. Radiographs should not be obtained routinely when MRI is

Image post-processing of dental digitalradiographs, a function which used commonly in dental practice is presented in this article. Digital radiography has been available in dentistry for more than 25 years and its use by dental practitioners is steadily increasing. Digital acquisition of radiographs enables computer-based image post-processing to enhance image quality and increase the accuracy of interpretation. Image post-processing applications can easily be practiced in dental office by ...

Confocal microscopy, which is a major advance upon normal light microscopy, has been used in a number of scientific fields. By confocal microscopy techniques, cells and tissues can be visualized deeply, and three-dimensional images created. Compared with conventional microscopes, confocal microscope improves the resolution of images by eliminating out-of-focus light. Moreover, confocal microscope has a higher level of sensitivity due to highly sensitive light detectors and the ability to accumulate images captured over time. In present studies, a series of Weeping Forsythia pollen digitalimages (35 images in total) were acquired with confocal microscope, and the three-dimensional digitalimage of the pollen reconstructed with confocal microscope. Our results indicate that it's a very easy job to analysis threedimensional digitalimage of the pollen with confocal microscope and the probe Acridine orange (AO).

Digital watermarking technique has been presented and widely researched to solve some important issues in the digital world, such as copyright protection, copy protection and content authentication. Several robust watermarking schemes based on vector quantization (VQ) have been presented. In this paper, we present a new digitalimage watermarking method based on SOFM vector quantizer for color images. This method utilizes the codebook partition technique in which the watermark bit is embedded into the selected VQ encoded block. The main feature of this scheme is that the watermark exists both in VQ compressed image and in the reconstructed image. The watermark extraction can be performed without the original image. The watermark is hidden inside the compressed image, so much transmission time and storage space can be saved when the compressed data are transmitted over the Internet. Simulation results demonstrate that the proposed method has robustness against various image processing operations without sacrif...

Imaging through turbid media using visible or IR light instead of harmful x ray is still a challenging problem, especially in dynamic imaging. A method of dynamic imaging through turbid media using digital holography is presented. In order to match the coherence length between the dynamic object wave and the reference wave, a cw laser is used. To solve the problem of difficult focusing in imaging through turbid media, an autofocus technology is applied. To further enhance the image contrast, a spatial filtering technique is used. A description of digital holography and experiments of imaging the objects hidden in turbid media are presented. The experimental result shows that dynamic images of the objects can be achieved by the use of digital holography.

International audience; Surface patterning by e-beam lithography and SEM imaging distortions are studied via digitalimage correlation. The global distortions from the reference pattern, which has been numerically generated, are first quantified from a digitalimage correlation procedure between the (virtual) reference pattern and the actual SEM image both in secondary and backscattered electron imaging modes. These distortions result from both patterning and imaging techniques. These two con...

The design and operation of a new generation of digitalimaging riometer systems developed by Lancaster University are presented. In the heart of the digitalimaging riometer is a field-programmable gate array (FPGA), which is used for the digital signal processing and digital beam forming, completely replacing the analog Butler matrices which have been used in previous designs. The reconfigurable nature of the FPGA has been exploited to produce tools for remote system testing and diagnosis which have proven extremely useful for operation in remote locations such as the Arctic and Antarctic. Different FPGA programs enable different instrument configurations, including a 4 × 4 antenna filled array (producing 4 × 4 beams), an 8 × 8 antenna filled array (producing 7 × 7 beams), and a Mills cross system utilizing 63 antennas producing 556 usable beams. The concept of using a Mills cross antenna array for riometry has been successfully demonstrated for the first time. The digital beam forming has been validated by comparing the received signal power from cosmic radio sources with results predicted from the theoretical beam radiation pattern. The performances of four digitalimaging riometer systems are compared against each other and a traditional imaging riometer utilizing analog Butler matrices. The comparison shows that digitalimaging riometer systems, with independent receivers for each antenna, can obtain much better measurement precision for filled arrays or much higher spatial resolution for the Mills cross configuration when compared to existing imaging riometer systems.

The conventional optical microscope has been the primary tool in assisting pathological examinations. The modern digital pathology combines the power of microscopy, electronic detection, and computerized analysis. It enables cellular-, molecular-, and genetic-imaging at high efficiency and accuracy to facilitate clinical screening and diagnosis. This paper first reviews the fundamental concepts of microscopic imaging and introduces the technical features and associated clinical applications of optical microscopes, electron microscopes, scanning tunnel microscopes, and fluorescence microscopes. The interface of microscopy with digitalimage acquisition methods is discussed. The recent developments and future perspectives of contemporary microscopic imaging techniques such as three-dimensional and in vivo imaging are analyzed for their clinical potentials.

Foot problems are extremely common in elephants and radiography is the only imaging method available but the radiographic anatomy has not been described in detail. The aims of this study were to develop a radiographic protocol for elephant feet using digital radiography, and to describe the normal radiographic anatomy of the Asian elephant front and hind foot. A total of fifteen cadaver foot specimens from captive Asian elephants were radiographed using a range of projections and exposures to determine the best radiographic technique. This was subsequently tested in live elephants in a free-contact setting. The normal radiographic anatomy of the Asian elephant front and hind foot was described with the use of three-dimensional models based on CT reconstructions. The projection angles that were found to be most useful were 65-70° for the front limb and 55-60° in the hind limb. The beam was centred 10-15 cm proximal to the cuticle in the front and 10-15 cm dorsal to the plantar edge of the sole in the hind foot depending on the size of the foot. The protocol developed can be used for larger-scale diagnostic investigations of captive elephant foot disorders, while the normal radiographic anatomy described can improve the diagnostic reliability of elephant feet radiography.

Full Text Available INTRODUCTION: Biological age is an important parameter for growth and development assessment. It can be evaluated through the observation of radiographic changes in skeletal maturation of cervical vertebrae. OBJECTIVE: This study aims to: a verify if there is correlation between growth curve and the stages of bone age of animals used in laboratories, by evaluating radiographs of the cervical vertebrae; b correlate these stages with their correspondents in humans. METHODS: 35 Wistar rats were evaluated for a period of 160 days, starting at day 22nd (weaning, with cross sections for periodic weighing, length measurement and digital radiography. Radiographs of the cervical vertebrae (C2 and C3 were measured by means of a computer program (Radio IMP. Data were submitted to statistical analysis (ANOVA and Pearson correlation. RESULTS: Growth spurt was characterized by fast increasing in weight and length. Through ANOVA, differences were observed in the cervical measurements between days 22, 97, 127, 157, 187 and 217 (p <0.001. A high correlation was found between increasing in body length and weight, as well as in cervical vertebrae height (r = 0.86. Increments in concavities of vertebrae were also observed, similar to humans. CONCLUSIONS: There is correlation between body growth and maturation of cervical vertebrae in rats. Despite the continuous development of concavities, it was not possible to clearly identify the 5/6 stages as in studies of cervical vertebrae maturation in humans.

This paper investigates the requirements for image processing of digital chest X-ray images. These images are conventionally recorded on film and are characterised by large size, wide dynamic range and high resolution. X-ray detection systems are now becoming available for capturing these images directly in photoelectronic-digital form. In this report, the hardware and software facilities required for handling these images are described. These facilities include high resolution digitalimage displays, programmable video look up tables, image stores for image capture and processing and a full range of software tools for image manipulation. Examples are given of the application of digitalimage processing techniques to this class of image.

The dentist considering adopting digital radiological technology should consider more than the type of detector with which to capture the image. He\\/she should also consider the mode of display, image enhancement, radiation dose reduction, how the image can be stored long term, and infection control.

A method for determining the locations of the major edges of objects in digitalimages is presented. The method is based on an algorithm utilizing maximum likelihood concepts. An image line-scan interval is processed to determine if an edge exists within the interval and its location. The proposed algorithm has demonstrated good results even in noisy images.

This is part two of a two-part study in benchmarking system performance of fixed digitalradiographic systems. The study compares the system performance of seven fixed digital radiography systems based on quantitative metrics like modulation transfer function (sMTF), normalised noise power spectrum (sNNPS), detective quantum efficiency (sDQE) and entrance surface air kerma (ESAK). It was found that the most efficient image receptors (greatest sDQE) were not necessarily operating at the lowest ESAK. In part one of this study, sMTF is shown to depend on system configuration while sNNPS is shown to be relatively consistent across systems. Systems are ranked on their signal-to-noise ratio efficiency (sDQE) and their ESAK. Systems using the same equipment configuration do not necessarily have the same system performance. This implies radiographic practice at the site will have an impact on the overall system performance. In general, systems are more dose efficient at low dose settings.

Presents the results of a qualitative study that focuses on search patterns of college students and community users interacting with a digitalimage collection. The study finds a distinct difference between the two groups of users and examines the role of mental models in information seeking behavior in digital libraries.

Provides an overview of the British Library's Initiatives for Access program which uses digitalimaging. Highlights include digitization of microfilm, the electronic "Beowulf", electronic photographic viewing system, computer software that uses neural networks and fuzzy matching to provide links to search terms, and international projects. (LRW)

Presents the results of a qualitative study that focuses on search patterns of college students and community users interacting with a digitalimage collection. The study finds a distinct difference between the two groups of users and examines the role of mental models in information seeking behavior in digital libraries.

Technology educators who teach digital photography should consider incorporating an infrared (IR) photography component into their program. This is an area where digital photography offers significant benefits. Either type of IR imaging is very interesting to explore, but traditional film-based IR photography is difficult and expensive. In…

Technology educators who teach digital photography should consider incorporating an infrared (IR) photography component into their program. This is an area where digital photography offers significant benefits. Either type of IR imaging is very interesting to explore, but traditional film-based IR photography is difficult and expensive. In…

Digitalimage-processing techniques developed for processing pictures from NASA space vehicles are analyzed in terms of enhancement, quantitative restoration, and information extraction. Digital filtering, and the action of a high frequency filter in the real and Fourier domain are discussed along with color and brightness.

In this paper we present the first tests of a digitalimaging system based on a silicon pixel detector bump-bonded to an integrated circuit operating in single photon counting mode. The X-rays sensor is a 300 mu m thick silicon, 14 by 14 mm/sup 2/, upon which a matrix of 256 * 256 pixels has been built. The read-out chip, named MEDIPIX2, has been developed at CERN within the MEDIPIX2 Collaboration and it is composed by a matrix of 256 * 256 cells, 55 * 55 mu m/sup 2/. The spatial resolution properties of the system have been assessed by measuring the square wave resolution function (SWRF) and first images of a standard mammographic phantom were acquired using a radiographic tube in the clinical irradiation condition. (5 refs).

The performances of a number of block-based, reversible, compression algorithms suitable for compression of very-large-format images (4096x4096 pixels or more) are compared to that of a novel two-dimensional linear predictive coder developed by extending the multichannel version of the Burg algorithm to two dimensions. The compression schemes implemented are: Huffman coding, Lempel-Ziv coding, arithmetic coding, two-dimensional linear predictive coding (in addition to the aforementioned one), transform coding using discrete Fourier-, discrete cosine-, and discrete Walsh transforms, linear interpolative coding, and combinations thereof. The performances of these coding techniques for a few mammograms and chest radiographsdigitized to sizes up to 4096x4096 10 b pixels are discussed. Compression from 10 b to 2.5-3.0 b/pixel on these images has been achieved without any loss of information. The modified multichannel linear predictor outperforms the other methods while offering certain advantages in implementation.

The radiology is a field of medicine that is in constantly expansion and advancing. This can be noticed with the transition from analog to digital radiology systems, it is important that professionals understand image formation in both systems in order to produce radiographies with diagnostic quality. Therefore, the objective of this work is to present the importance of radiological protection by changing values of technical parameters while the quality of radiographicimaging is sustained. An anthropomorphic hand phantom was built in order to obtain radiographies, as it is necessary to respect the Brazilian regulations (Portaria 453/98) which forbids the use of radiation in patients for testing. Three analog and eight digital radiographies were obtained using fixed kVp and varying mAs. Each image was compared to the others acquired in the same location. Digital radiographies have shown that approximately 28% of change in mAs is necessary to change noise, whereas approximately 33,3% is necessary in the analog system to change density. The conclusion is that computerized systems need less x-ray intensity to modify image features and can reduce the patient radiation doses. However, more testing must be conducted in different radiologic environments to confirm the results obtained in the present study. (author)

Nine specific techniques of combination of techniques developed for applying digitalimage processing technology to existing astronomical imagery are described. Photoproducts are included to illustrate the results of each of these investigations.

Full Text Available The main image information content, from the human visual system viewing point, is focused into whole colorimetric and spatial informations. Because every image is result of some previous processes, the goal for all standard image processing methods is improvement colorimetric and spatial image parameters in relation maximum information content by the complicated and expensive systems for digitalimage processing in (quasireal time [1] based on the flash signal (multiprocessors. Some single-purpose applications do not need the robust and flash systems for DIP and be enough for their use single digital filters with suitable hardware implementation. In the contribution discussed problem is therefore focused on the short description of FIR digital tilters and their hardware implementation in FPGAs-Xilinx for usage in the image processing in real time include obtained experimental results.

The development of a digitalimage processing system for bone histomorphometry and fluorescent marker monitoring is discussed. The system in question is capable of making measurements of UV or light microscope features on a video screen with either video or computer-generated images, and comprises a microscope, low-light-level video camera, video digitizer and display terminal, color monitor, and PDP 11/34 computer. Capabilities demonstrated in the analysis of an undecalcified rat tibia include the measurement of perimeter and total bone area, and the generation of microscope images, false color images, digitizedimages and contoured images for further analysis. Software development will be based on an existing software library, specifically the mini-VICAR system developed at JPL. It is noted that the potentials of the system in terms of speed and reliability far exceed any problems associated with hardware and software development.

The paper gives a brief presentation of digital and archiving imaging system (PACS) with a survey of the main characteristics and development of the system worldwide as well as the possibilities and the area of its implementation in our conditions. We have given a proposition for digitalization and archiving of both the existing and future medical imaging in accordance with our possibilities for world standards implementation.

Departing from a technofeminist perspective, Becoming Image, places the digitalimage in a broader context of modern and postmodern technological discourses and fashion. In four articles, the compilation dissertation expands a contemporary and imagistic tech discourse by questioning the ideology of ”masculinity”―specifically the idea of it as a historically male domain. Through interviews, discourse analysis and feminist critique, as well as an interdisciplinary focus on digital media, the pr...

Segmentation in computer vision refers to the process of partitioning a digitalimage into multiple segments (sets of pixels). It has several features which make it suitable for techniques inspired by nature. It can be parallelized, locally solved and the input data can be easily encoded by bio-inspired representations. In this paper, we present a new software for performing a segmentation of 2D digitalimages based on Membrane Computing techniques.

Contrast-enhanced magnetic resonance imaging with maximum intensity projection (MRI-MIP) is an easy, useful imaging method to evaluate synovitis in rheumatoid hands. However, the prognosis of synovitis-positive joints on MRI-MIP has not been clarified. The aim of this study was to evaluate the relationship between synovitis visualized by MRI-MIP and joint destruction on X-rays in rheumatoid hands. The wrists, metacarpophalangeal (MP) joints, and proximal interphalangeal (PIP) joints of both hands (500 joints in total) were evaluated in 25 rheumatoid arthritis (RA) patients. Synovitis was scored from grade 0 to 2 on the MRI-MIP images. The Sharp/van der Heijde score and Larsen grade were used for radiographic evaluation. The relationships between the MIP score and the progression of radiographic scores and between the MIP score and bone marrow edema on MRI were analyzed using the trend test. As the MIP score increased, the Sharp/van der Heijde score and Larsen grade progressed severely. The rate of bone marrow edema-positive joints also increased with higher MIP scores. MRI-MIP imaging of RA hands is a clinically useful method that allows semi-quantitative evaluation of synovitis with ease and can be used to predict joint destruction.

Aims: To investigate the diagnostic quality of different quality, individually calibrated ink-jet printers for the very challenging dental radiographic task of approximal carious lesion detection. Materials and methods: A test-pattern evaluating resolution, contrast and homogeneity of the ink-jet prints was developed. 50 standardized dental radiographs each showing two neighbouring teeth in natural contact were printed on glossy paper with calibrated, randomly selected ink-jet printers (Canon S520 and iP4500, Epson Stylus Photo R2400). Printing size equalled the viewing size on a 17'' cathode-ray-tube monitor daily quality-tested according to German regulations. The true caries status was determined from serial sectioning and microscopic evaluation. 16 experienced observers evaluated the radiographs on a five-point confidence scale on all prints plus the viewing monitor with respect to the visibility of a carious lesion. A non-parametric Receiver-Operating Characteristics (ROC-) analysis was performed explicitly designed for the evaluation of readings stemming from identical samples but different modality. Significant differences are expressed by a critical ratio z exceeding {+-}2. Diagnostic accuracy was determined by the area (Az) underneath the ROC-curves. Results: Average Az-values ranged between 0.62 (S520 and R2400) and 0.64 (monitor, iP4500), with no significant difference between modalities (P = 0.172). Neither significant (range mean z: -0.40 (S520) and -0.11 (iP4500)) nor clinically relevant differences were found between printers and viewing monitor. Conclusions: Our results for a challenging task in dental radiography indicate that calibrated, off-the-shelf ink-jet printers are able to reproduce (dental) radiographs at quality levels sufficient for radiographic diagnosis in a typical dental working environment.

In dermatology, various digitalimaging modalities have been used as an important tool to quantitatively evaluate the treatment effect of skin lesions. Cross-polarization color image was used to evaluate skin chromophores (melanin and hemoglobin) information and parallel-polarization image to evaluate skin texture information. In addition, UV-A induced fluorescent image has been widely used to evaluate various skin conditions such as sebum, keratosis, sun damages, and vitiligo. In order to maximize the evaluation efficacy of various skin lesions, it is necessary to integrate various imaging modalities into an imaging system. In this study, we propose a multimodal digital color imaging system, which provides four different digital color images of standard color image, parallel and cross-polarization color image, and UV-A induced fluorescent color image. Herein, we describe the imaging system and present the examples of image analysis. By analyzing the color information and morphological features of facial skin lesions, we are able to comparably and simultaneously evaluate various skin lesions. In conclusion, we are sure that the multimodal color imaging system can be utilized as an important assistant tool in dermatology.

Han, Won Jeong [Dankook University College of Medicine, Seoul (Korea, Republic of)

2004-03-15

To evaluate the diagnostic accuracy of occlusal and proximal caries detection using CCD, CMOS, PSP and film system. 32 occlusal and 30 proximal tooth surfaces were radiographed under standardized conditions using 3 digital systems; CCD (CDX-2000HQ, Biomedysis Co., Seoul, Korea), CMOS (Schick, Schick Inc., Long Island, USA), PSP (Digora FMX, Orion Co./Soredex, Helsinki, Finland) and 1 film system (Kodak Insight, Eastman Kodak, Rochester, USA). 5 observers examined the radiographs for occlusal and proximal caries using a 5-point confidence scale. The presence of caries was validated histologically and radiographically. Diagnostic accuracy was evaluated using ROC curve areas (AZ). Analysis using ROC curves revealed the area under each curve which indicated a diagnostic accuracy. For occlusal caries, Kodak Insight film had an Az of 0.765, CCD one of 0.730, CMOS one of 0.742 and PSP one of 0.735. For proximal caries, Kodak Insight film had an Az of 0.833, CCD one of 0.832, CMOS one of 0.828 and PSP one of 0.868. No statistically significant difference was noted between any of the imaging modalities. CCD, CMOS, PSP and film performed equally well in the detection of occlusal and proximal dental caries. CCD, CMOS and PSP-based digitalimages provided a level of diagnostic performance comparable to Kodak Insight film.

Orthogonal rotation-invariant moments (ORIMs), such as Zernike moments, are introduced and defined on a continuous unit disk and have been proven powerful tools in optics applications. These moments have also been digitized for applications in digitalimage processing. Unfortunately, digitization compromises the orthogonality of the moments and, therefore, digital ORIMs are incapable of representing subtle details in images and cannot accurately reconstruct images. Typical approaches to alleviate the digitization artifact can be divided into two categories: 1) careful selection of a set of pixels as close approximation to the unit disk and using numerical integration to determine the ORIM values, and 2) representing pixels using circular shapes such that they resemble that of the unit disk and then calculating ORIMs in polar space. These improvements still fall short of preserving the orthogonality of the ORIMs. In this paper, in contrast to the previous methods, we propose a different approach of using numerical optimization techniques to improve the orthogonality. We prove that with the improved orthogonality, image reconstruction becomes more accurate. Our simulation results also show that the optimized digital ORIMs can accurately reconstruct images and can represent subtle image details.

A high resolution, direct-digital detector system based upon a 2-D silicon microstrip sensor has been designed, built and is undergoing evaluation for applications in dentistry and mammography. The sensor parameters and image requirements were selected using Monte Carlo simulations. Sensors selected for evaluation have a strip pitch of 50mum on the p-side and 80mum on the n-side. Front-end electronics and data acquisition are based on the APV6 chip and were adapted from systems used at CERN for high-energy physics experiments. The APV6 chip is not self-triggering so data acquisition is done at a fixed trigger rate. This paper describes the mammographic evaluation of the double sided microstrip sensor. Raw data correction procedures were implemented to remove the effects of dead strips and non-uniform response. Standard test objects (TORMAX) were used to determine limiting spatial resolution and detectability. MTFs were determined using the edge response. The results indicate that the spatial resolution of the...

We provide conditions under which 2D digitalimages preserve their topological properties under rigid transformations. We consider the two most common digital topology models, namely dual adjacency and well-composedness. This paper leads to the proposal of optimal preprocessing strategies that ensure the topological invariance of images under arbitrary rigid transformations. These results and methods are proved to be valid for various kinds of images (binary, gray-level, label), thus providing generic and efficient tools, which can be used in particular in the context of image registration and warping.

A self-contained approach to DSP techniques and applications in radar imagingThe processing of radar images, in general, consists of three major fields: Digital Signal Processing (DSP); antenna and radar operation; and algorithms used to process the radar images. This book brings together material from these different areas to allow readers to gain a thorough understanding of how radar images are processed.The book is divided into three main parts and covers:* DSP principles and signal characteristics in both analog and digital domains, advanced signal sampling, and

To improve the versatility and usability of optical correlators, we developed an optical-digital hybrid image search system consisting of digital servers and an optical correlator that can be used to perform image searches in the cloud environment via a web browser. This hybrid system employs a simple method to obtain correlation signals and has a distributed network design. The correlation signals are acquired by using an encoder timing signal generated by a rotating disk, and the distributed network design facilitates the replacement and combination of the digital correlation server and the optical correlator.

To determine the effect of degraded digitalimage resolution (as viewed on a monitor) on the accuracy and confidence of dermatologic interpretation. Eight dermatologists interpreted 180 clinical cases divided into three Logical Competitor Sets (LCS) (pigmented lesions, non-pigmented lesions, and inflammatory dermatoses). Each case was digitized at three different resolutions. The images were randomized and divided into (9) 60-image sessions. The physicians were completely blinded concerning the image resolution. After 60 seconds per image, the viewer recorded a diagnosis and level of confidence. The resultant ROC curves compared the effect of LCS, level of clinical difficulty, and resolution of the digitalimage. One-way analysis of variance (ANOVA) compared the curves. The areas beneath the ROC curves did not demonstrate any consistently significant difference between the digitalimage resolutions for all LCS and levels of difficulty. The only significant effect observed was amongst pigmented lesions (LCS-A) where the ROC curve area was significantly smaller in the easy images at high resolution compared to low and medium resolutions. For all other ROC curve comparisons within LCS-A, at all other levels of difficulty, as well as within the other LCS at all levels of difficulty, none of the differences was significant. A 720 x 500 pixel image can be considered equivalent to a 1490 x 1000 pixel image for most store-and-forward teledermatology consultations.

Kansas Data Access and Support Center — This data set contains imagery from the National Agriculture Imagery Program (NAIP). NAIP acquires digital ortho imagery during the agricultural growing seasons in...

Full Text Available The purpose of this research was to compare two digital storage phosphor systems and conventional film, as well as verify the interexaminer agreement in radiographic diagnosis on occlusal and proximal cavities. Two digital systems and conventional radiographic film were used to evaluate 144 tooth surfaces with and without cavities; the radiographs were analyzed and scored in a scale of 4 points. Thirteen undergraduates and an oral radiologist participated as examiners. A light microscopy analysis was accomplished in order to validate the research. The results showed that there was no significant difference between the radiographic systems, however all of them had significant differences when compared to light microscopy, except for the Digora system on the proximal surface when the radiologist was the examiner. In the interexaminer evaluation, a moderate agreement level was obtained, and a fair to moderate level was obtained between the students and the oral radiologist. Regarding the validation (sensitivity, specificity, positive predict and negative predict the values were similar between students and the oral radiologist, except for the sensitivity value on the occlusal surface. The students had the highest number of false-positive results and the oral radiologist the highest number of false-negative results.O objetivo desta pesquisa foi comparar dois sistemas digitais de armazenamento de fósforo e filme convencional, assim como verificar a concordância interexaminadores em diagnóstico radiográfico de cáries oclusais e proximais. Dois sistemas radiográficos digitais e filme convencional foram usados para avaliar 144 superfícies dentais com e sem cavitação; as radiografias foram analisadas e classificadas em uma escala de 4 pontos. Participaram como examinadores 13 alunos de graduação e um radiologista odontológico. Para validar esta pesquisa foram realizadas análises em microscopia ótica. Os resultados mostraram não haver

The ''arcuate sign'' is considered a pathognomonic sign for injuries of the posterolateral (PL) corner of the knee. The purpose of our study was to identify different patterns of injury to the fibular head that may associate with injuries to specific ligaments and tendons of the PL corner of the knee. The anatomic relations between the insertions of fibular collateral ligament (FCL), biceps femoris tendon (BFT), popliteofibular ligament (PFL), and arcuate ligament in normal cadaveric knees were also investigated. Magnetic resonance imaging was performed in two cadaveric knees which subsequently were dissected. Radiopaque markers were placed upon the fibular insertions of the FCL, BFT, PFL, and arcuate ligament in the dissected knees, and knee radiographs were then obtained. Twelve patients with radiographic or MR imaging evidence of isolated injury to the PL corner of the knee were retrospectively reviewed, with regard to avulsion fractures and marrow edema in the fibular head and the integrity of the ligaments of the PL corner of the knee. The PFL and arcuate ligament were seen to attach directly to the posterior and medial aspect of the styloid process of the fibular head. The FCL and BFT attached as a conjoined structure on the lateral aspect of the fibular head lateral, anterior and inferior to the attachment site of the PFL and arcuate ligament. Injury to the arcuate ligament or PFL was diagnosed in 8 patients who presented with a small avulsion fracture of the styloid process of the fibula (n=2), bone marrow edema in the medial aspect of the fibular head (n=3), or both (n=3). In 4 patients with injury to the conjoined tendon or FCL, a larger avulsion fragment and more diffuse proximal fibular edema were seen. Radiographic and MR imaging findings in injuries of the posterolateral corner of the knee may suggest injury to specific structures inserting in the fibular head. (orig.)

Abstract The printing industry has experienced cyclical change throughout its history. Since the advent of early hand-operated printing presses to the introduction of mechanical, high-volume technology the industry has evolved, for the most part, incrementally. Printing firms have capitalised on developments with various degrees of success. The industry currently faces a radical shift with the advent of digital printing technology. When digital was introduced in 1993, predictions th...

Full Text Available High resolution satellite images are widely used to produce and update a digital map since they became widely available. It is well known that the accuracy of digital map produced from satellite images is decided largely by the accuracy of geometric modelling. However digital maps are made by a series of photogrammetric workflow. Therefore the accuracy of digital maps are also affected by the quality of satellite images, such as image interpretability. For satellite images, parameters such as Modulation Transfer Function(MTF, Signal to Noise Ratio(SNR and Ground Sampling Distance(GSD are used to present images quality. Our previous research stressed that such quality parameters may not represent the quality of image products such as digital maps and that parameters for image interpretability such as Ground Resolved Distance(GRD and National Imagery Interpretability Rating Scale(NIIRS need to be considered. In this study, we analyzed the effects of the image quality on accuracy of digital maps produced by satellite images. QuickBird, IKONOS and KOMPSAT-2 imagery were used to analyze as they have similar GSDs. We measured various image quality parameters mentioned above from these images. Then we produced digital maps from the images using a digital photogrammetric workstation. We analyzed the accuracy of the digital maps in terms of their location accuracy and their level of details. Then we compared the correlation between various image quality parameters and the accuracy of digital maps. The results of this study showed that GRD and NIIRS were more critical for map production then GSD, MTF or SNR.

The watermarking technique has been proposed as a method by hiding secret information into the im age to protect the copyright of multimedia data. But most previous work focuses on the algorithms of embedding one-dimensional watermarks or two-dimensional binary digital watermarks. In this paper, a wavelet-based method for embedding a gray-level digital watermark into an image is proposed. By still image decomposition technique, a gray-level digital watermark is decompounded into a series of bitplanes. By discrete wavelet transform ( DWT ), the host image is decomposed into multiresolution representations with hierarchical structure. Thedifferent bitplanes of the gray-level watermark is embedded into the corresponding resolution of the decomposed host image. The experimental results show that the proposed techniques can successfully survive image processing operations and the lossy compression techniques such as Joint Photographic Experts Group (JPEG).

This paper presents the analysis and management system of digital ultrasonic image. The system can manage medical ultrasonic image by collecting, saving and transferring, and realize that section offices of ultrasonic image in hospital network manage. The system use network technology in transferring image between ultrasonic equipments to share patient data in ultrasonic equipments. And doctors can input patient diagnostic report,saved by text file and case history, digitally managed. The system can be realized by Visual C++ which make windows applied. The system can be brought forward because PACS prevail with various hospitals,but PACS is expensive. In view of this status, we put forward to the analysis and management system of digital ultrasonic image,which is similar to PACS.

The advent and wide use of antibiotics have decreased the incidence of deep neck infection. When a deep neck infection does occur, however, it can be the cause of significant morbidity and death, resulting in airway obstruction, mediastinitis, pericarditis, epidural abscesses, and major vessel erosion. In our clinic, a patient with diffuse chronic osteomyelitis of mandible and fascial space abscess and necrotic fasciitis due to odontogenic infection at the time of first visit came. We successfully treated the patient by early diagnosis using contrast-enhanced CT and follow up dressing through the appropriate use of radiographicimages.

The long bones of the hands and feet in children have an epiphyseal end with a secondary center of ossification and an adjacent transverse physis. In contrast to other long bones in the body, the opposite end in the hands and feet, termed the non-epiphyseal end, is characterized by direct metaphyseal extension of bone to complete terminal ossification. The purpose of this pictorial essay is to illustrate the developmental stages of each end of the long bones of the hands and feet with radiographic and MR imaging to provide a foundation from which to differentiate normal from abnormal growth. (orig.)